My Arduino is forfeited. Arduino IDE cannot detect the port. I don't know the name of component. Can I fix it?
Here is the picture. In te circle red, the component is forfeited
That appears to be a voltage regulator. If it burned out, it is likely that many other components on the board are also burned.
Best to buy a new Arduino.
It's the 5 volt regulator. It means that either you gave it too high of an input voltage, or drew too much current from the 5 volt pin. You can desolder it, and replace it with a new one. However, I suspect there has been more damage, since the regulator alone would not preclude seeing the device on the usb port.
As jremmington says, get a new one, but figue out what went wrong first!
It's the 5V voltage regulator.
Two scenarios is possible:
1: It's shorting out the 5V-rail and therefore stopping the main Atmega2560-chip from getting power from the USB-cable.
2: The voltage regulator was blown up in such spectacular way that everything else downstream is cooked. In that case, get a new one.
Easy way to test for 1: Desolder the broken regulator. Does the board work then? Then you just need to get a new regulator.
Still, please when making posts like this - EXPLAIN what happened before you fucked it up. It makes it so much easier to fault find after.
// Per.
"Desolder the regulator" can be replaced by "Destroy it until there is no physical connection between any of the pins." Crush it with pliers. Twist it off the board until the copper pads tear up and come away with it.
It may still be useable as a USB-only device. Useful to check small pieces of code that only need to blink an LED.
Before you burn up the next one, you need to review what is powered from the 5V and 3.3V provided by the Arduino.
these are the components that get burnt out most often in this situation, there may be more damage though. The image of the arduino is attached.
TeachMe:
I don't know the name of component. Can I fix it?
The regulator component is destroyed. That regulator component can't be fixed unfortunately. Replacing the regulator is an option, but it's possible that other components are destroyed too --- since you mentioned that the computer can't detect the arduino via usb. So it doesn't sound promising right now.
But if you're interested in what that particular busted component is .... "AMS1117-5.0 LM1117 5V 1A SOT-223 LDO Voltage Regulator"
Such dramatic destruction of the regulator suggests that it has been powered in reverse polarity or grossly excessive voltage - simply overloading the output would certainly not do this.
Remove the regulator. Crushing with nippers would be a start, then un-solder the remains.
Replacing the regulator is not advised if only because you really should not be powering the UNO via "Vin" or the "barrel jack" in the first place for any serious project. Use a USB "phone charger" to power it via the USB port to first test it and if it passes, do other projects. If you can guarantee you will not connect it wrongly (again!), you can power it via the 5 V pin from whatever 5 V regulated power supply you use to power other devices.
Brilliant! Thank you very much for the information. It's funny, I saw a port like notebook's charger so I plug in my charger to the port, and poof! The regulator get smoked. How stupid I am.
TeachMe:
Brilliant! Thank you very much for the information. It's funny, I saw a port like notebook's charger so I plug in my charger to the port, and poof! The regulator get smoked. How stupid I am.
It probably had the negative on the inside, and the positive outside. ... whoops!
If you look on the wall wart, there should be a tiny little diagram that shows you which one is positive and which is negative, so next time you can check.
ChrisTenone:
It probably had the negative on the inside, and the positive outside. ... whoops!
OK, I didn't mention it before for simplicity, but that is specifically why the UNO has a diode in series with the barrel jack. 
You can only reverse-power the regulator by connecting to "Vin".
No, he said
TeachMe:
I saw a port like notebook's charger so I plug in my charger to the port, and poof!
Note the words "notebook's charger". 19 Volts. 
Probably 7 Amps too.
The label would tell you that too!
If the 5V regulator was dead, try removing it and then talking to the board over USB. If that doesn't work, the Atmega16U2 is likely dead and you are basically out of luck without a hot air rework station to remove & replace parts.
That's funny I just smoked mine... stupid RJ11 crossover. Crossover is the dumbest idea in the history of man. Needless to say I hooked up ground to 5V bus (I thought it was A0) unwittingly then saw smoke.