On‐chip optical polarizer can extract the desired polarized light signal while filtering out the other polarized light signal, which plays a key role in integrated photonic circuits for purifying the desired polarized signal and reducing polarization crosstalk. However, most of the reported optical polarizers can only work for fundamental modes. With the rapid development of on‐chip multimode processing systems, arbitrary high‐order mode optical polarizers are more desirable. In this contribution, a TM‐pass optical multimode polarizer is proposed and demonstrated using subwavelength grating‐based anisotropic manipulation, which can achieve the polarizing of arbitrary TM high‐order mode theoretically, and the experimental results show the lowest polarization extinction ratio of the fabricated device can reach up to 21.2 dB under working for four‐mode (TM0, TM1, TM2, and TM3) system. The dynamic data transmission with the data rate of 64 Gbit s−1 has also been demonstrated to verify its potential for systematized applications in the future.