In ancient Chinese art criticism, there were such artistic creation methods as Shi Xin (follow heart), Shi Gu (follow the ancient) and Shi Zaohua(follow creation), which provide reference for artistic creation in the process of art evaluation in past dynasties. In different times and schools, the objects of Shi Fa(follow the law) in artistic creation were different, which reflected the value and aesthetic orientation of art and artists at that time and became the benchmark and reference for artistic creation in the same period. By combing the art criticism literature on Shi Fa through ancient dynasties, this paper analyzes the changes of the object of Shi Fa with the background of specific historical periods, analyzes the artistic category of Yi(freedom) produced in the deviation from and return to Fa(law), studies the "two-way" interaction between the subject and object in the aesthetic connotation of Shi Fa, and summarizes the evolution of Shi Fa in the art criticism thought in ancient dynasties in China and the deviation from and return to Fa.