A polarization-independent beam splitter (PIBS) based on self-collimation Mach–Zehnder interferometer (SMZI) in a hole-type silicon photonic crystal (PC) is proposed and numerically demonstrated. Utilizing polarization dependence of the transmission spectra of the SMZI and polarization transmission matching method, the SMZI can work as a PIBS by selecting appropriate path length difference in the structure. For a certain operating frequency, the PIBS has the same splitting ratio for both transverse-electric mode and transverse-magnetic mode. In this paper, the PIBS with splitting ratios of and is designed and numerically demonstrated, respectively. For the operating wavelength of 1550 nm, the sizes of the PIBS are only . With its small dimensions, simple structure, and silicon-based material, this PIBS may have practical applications in photonic-integrated circuits.