A kind of rectangular straight rack connecting structure is proposed for tight junction between movable beam and stand column,so as to ensure the load bearing entirety of movable beam and stand column in each stroke position. The contact stress contour under different loading and in different contact state is obtained by using finite element software MSC. Marc. The results show that the max contact stress is increased with the increasing of load,and when the load exceeds certain value,the max contact stress has a linear relation with load,and also the value and increase amplitude of max contact stress of fixed rack is much higher than that of movable rack; when the movable beam is in different stroke position,namely the structure has different contact state,the value of max contact stress didn’t change obviously,therefore,the structural strength can be checked on the basis of stress level of fixed rack.