In this paper, we propose a unidirectional wave guide based on valley Hall effect, which is composed of two kinds of photonic crystals with different topological properties. These two kinds of photonic crystals are composed of Al₇₀Ga₃₀As and Si dielectric cylinders, which can realize the unidirectional passage of light in the communication band. The simulation results show that the proposed structure can not only realize the large angle turn of the optical path, but also has good tolerance to defects, which provides a reference for the design of new optical waveguides with efficient optical transmission characteristics.