The optical beam propagation equation is solved by finite difference iterative method. The effect of the cross angle on the ratio of field intensity in the branch is studied about the 1×2(Y type) and 2×2(X type) couplers. The simulation results show that only the cross angle was controlled in a scale,the intensity ratio(1∶1) can not be effected in the branch of coupler. And the 2×2 coupler is sensitive to the cross angle and coupler width. It is a basic theoretic analysis for machining the passive fiber components with femtosecond laser.