The target device of my program is Winbond W78E516B with 64k Flash ROM and my program size is just 29k, I want to know why there is a error of "CLOCKCAL V1.C(1221): error C249: 'DATA': SEGMENT TOO LARGE" after compiling with Keil C.
"It is not relate to the 'bible time'"
Remember: when you post to an internet forum, nobody knows anything at all about you or your project other than what you explicitly state in your post.
From your post (which was all we had to go on) it looked distinctly like you didn't understand the different memory areas - specifically DATA and CODE - inherent to the 8051 architecture. Therefore, it was natural to suggest that you require 'bible time'
"my problem is just related to how to put the constant array table into the on chip XRAM or into the ROM"
Your original post did not mention anything about a constant array table, did it?