Plate heat exchanger can obtain higher thermal performance because of its advantages in high heat transfer coefficient, small scale, and can realize pure counter current flow. It has been widely applied in HVAC industry. In this paper, the numerical research of plate heat exchanger in solar heating system has been proposed. Aimed at the type of herringbone corrugated plate which has better thermal performance and been widely used, the three dimensional model is established by Gambit software. Using FLUENT software for numerical calculation, by studying the effect of corrugated inclination angle, corrugated depth, corrugated spacing and inlet velocity of heat exchanger on internal temperature, pressure, velocity distributions of domains, the relationship between the above parameters and the Nusselt Number and the pressure drop was obtained by simulation data. Heat transfer coefficient and pressure drop correlations used to measure the overall performance of the heat exchanger. The result shows that the optimal structure parameters is corrugated angle 60°, corrugated depth 4 mm and corrugated spacing 16 mm.