Abstract: Tetrahymena shanghaiensis S1 is a selfer strain. By starvation, more than 85% of the cells in a clone can be induced to conjugation synchronously. Using biochemical extraction, SDS-PAGE, combining with microscopic examination, we studied the major components and contents of cortical cytoskeleton protein of T.shanghaiensis S1, and explored the extraordinary changes in these proteins during conjugation for the first time.The similarity and difference between cortical cytoskeletal proteins of vegetation, conjugation and exconjugation cells are compared in this paper.The results of SDS-PAGE and protein isolation showed that the essential component of all cortical cytoskeleton proteins (225kD, 150kD、 120kD、52.5kD, 49kD、37-43kD) decreased during and after conjugation. We also observed great fluctuation of the 76-88kD proteins of the oral apparatus in different cell phases.Two particular bands are obvious: one is the 90kD protein and the other one is 85kD protein, both can be found after membrane fusion and during meiosis We recognice that during the conjugation proteins change obviously in all cortical cytoskeleton of T.shanghaiensis.