Particle impact drill bit is the key component for the particle impact drilling technology. In order to optimize the hydraulic structural parameters on the hydraulic performance of bit, a three-dimensional field model of bit was established. The CFD-based discrete particle model (DPM) was used to track the movement of the solid phase. The impact pressure on bottom hole and the cross flow speed were used to evaluate the hydraulic performance of PID bits. Sixteen models were built to analyze the effect of nozzle angle on the flow field. The results of numerical simulation showed that the impact pressure on the bottom hole increased firstly and then declined with the increase of nozzle angle. The cross-speed increased continuously. The optimal combination of radial distance and layout of the nozzles could produce an integrated bottom hole efficiently. Based on the simulation results, the layout of model 3-2 was the optimal. The results could provide a theoretical basis for the design of PID bit.