However, the Arduino Commands of millis() and micros() does not worked for me.
Without any explanation or code, all we can say is "Well, that's too bad. I guess your screwed."
I using Matlab software interface with Arduino Mega 2560 Board
I'm interested in how you loaded Matlab on your Mega.
that connected to MCP3008
Which is a ?
which able to write correct results (ADC value) into an excel file (.csv)
A csv file is NOT an Excel file. It is a comma separated values file that just happens to be a format that Excel knows how to read. So does Notepad++ and Word, but you'll never hear anyone refer to a csv file as a Notepad++ file or a Word file. You shouldn't be referring to csv files as Excel files, either.
Besides, I could not found the "Excel for Arduino application" in Microsoft Website
I'm shocked. Well, not really. More like mildly amused that you'd even look.