You started by saying,

"i want to know how to interface matrix keypad with 8052 my matrix keypad is 4*3"

Michael gave you an excellent illustration of how to do it; he used the 'C' programming language as his vehicle.

Now that you can see how it's done, you should be able to at least make a start on implementing that in assembler.

Or are you still not quite clear on how to do it? If so, tell us your specific problem.

Similarly, if you have some specific problem with writing the assembler - post it.

But at least have a go at it yourself - don't expect to receive the whole thing on a plate!
(that only happens in exchange for money - as Michael said)