In this study,point defects and line defects are introduced in a compl etely two- dimensional square lattice silicon,using the feature of coupling with point def ects and line defects,a 1×5equal-score beam splitter based on the two-dimensional photoni c crystal is proposed.The performance of beam splitter is studied by plane-wave-expansion method and finite-difference time-domain method.The research results show that 1.55μm i ncident light is transmitted to five port equally can be realized by changing the radius of diele ctric column in the coupling region;in order to improve the total transmittance,scattering med ium columns were added in the curved waveguide of the 1×5equal-score beam,and the releva nt parameters were optimized.At the same time,the transmittance reaches 99.65% an d the insertion loss is 0.015dB.The beam splitter is characterized by a smaller size, simple structure,low additional loss,which has important application prospect in futu re integrated optical circuit.