is a current 1 amp as input in pin harmful ? and what is max allowable value of it?
If you're talking about supplying power to the barrel or Vin, the Arduino will only use as much as is needed and 1A is OK (unless you short something ;) )
If you however try to sink or source 1 amp on an output pin (e.g. driving a motor) , you will blow up your processor.
If you're talking about a constant current source that drives an input pin directly (without resistor), I don't know.
i mean analog pin as input. the allowable volt is 5v but current that is the problem i wanna know max current value for each pin and how to get it from 5v 1amp source
Inputs (analog and digital) draw current. This means they act like e.g. a light bulb. A 60W light bulb (for 220V) draws 60/220 is approximately 0.25A. The fact that your electricity provider can deliver 40A or 100A or ... to your house does not change that and your light bulb does not blow because 40A is pushed through it.
The same applies in this case (as long as your source is a voltage source like e.g. a power supply).