Let (X,p1,p2)be a bitopological space ,a subset D of X is say to be open set (resp. closed set) in the bitopological spae X if it is open(resp. closed)set in (X,p1) or (X,p2). the concept of semi-open set in topological spaces was introduced in 1963by [N.Levine,1963]. [Levine, 1970]generalized the concept of closed sets to generalized closed sets . [Bhattacharya and Lahiri,1987] generalized the concept of closed sets to semi-generalized closed sets via semi-open sets .the complement of a semi-open(resp. semi-generalized-closed)set is called semi closed set [N.Levine,1970] (resp.semi-generalized open ). [ Kumar , 1991] introduced and defined a maps namely ?-continuity and he discus the relation between this map and semi –continuity [Biswas,N ,1970], generalized-continuity[Caldas,M ,1993], [R.Devi, H.Maki and K.Balachandran ,1993], [K.Balachandran ,P.Sundaram and H.Maki,1991], semi generalized -continuity[P.sundaram, H.Maki, K. Balachandran,1991], [P.Bhattacharya and B.K.Lahiri 1987] and generalized semi-continuity [Miguel Caladas Cueva and Ratnesh Kumar saraf ,2000]. The purpose of this paper that is give a new definition of these concepts in bitopological space(X,p1,p2)with some of its theorems and properties.