Abstract: The beam splitter based on photonic crystal waveguides is taken as an essential component in integrated optical circuits. A linear-defect 1×4 photonic crystal splitter was designed, and its characteristics were analyzed with the time-domain finite difference method. The experiment results show that the transmission properties at output end is dependent on the wavelength of incident light and the geometric shape of the branch, and the incident wave is divided equally into four output ports. The high transmittance can be obtained at each output port by adjusting the radii of the medium in the branching region to reduce the reflection of the 1×4 splitter at the three Y-branching regions.