hi, can anybody please help me to write code for ISP serial programming for AT89s52 device
There are a great many things to catch you out - especially if you're starting from scratch.
Given that well-established, free tools are already widely available, why do you want to do this?
"can u give me any basic idea to start"
Have you really not managed to find anything by looking on the Atmel site, using Google, etc? These are the basic steps that you need to start!