Abstract: This paper discussed the t-type s cuts and t cuts of occurrence nets.The concept of transfer sets were introduced and used to transfer one t cut to anather.The concept of t-type s cut was introduced,that there is correspondence between the set of t-type s cut and the set of t cuts was proved,that every t cut is the accompany set of a t-type s cut and that the transfer of a t cut correspond to the transfer of a t-type s cut with some transfer set were also proved.

Key words: Occurrence net,t cuts,Transfer set,t-type s cuts