In order to obtain ultra-broadly tunable optical wavelength signal splitting, we design optical signal splitter based on micro resonator in the two-dimensional photonic crystal structure. The performance of the optical signal splitter is qualitatively analyzed by coupled-mode theory under different design conditions. Operating characteristics of optical signal splitter with two symmetrical outputs are studied by the finite-difference time-domain method. The results show that the splitter achieves 29 and 38 passbands by adjusting the structures of micro resonators of 5×5 and relative dielectric constants of the whole rods, respectively. Channel waveguide dropping peak wavelength and bandwidth ranges are 1310.0~1655.5 nm and 2.0~7.4 nm, respectively. The structure has characteristics of broadly tunable passband, effectively removing noise signals, optical signal equal power splitting at the same peak wavelength. The proposed signal splitter structure has potential application value in the fields of coarse wavelength division demultiplexing design, optical signal equal power splitting design, integration of optical design, etc.