To solve the problems of large computational complexity and difficult hardware implementation of particle filters, the paper presents a simplified particle filter algorithm for bearings-only tracking, and uses Xilinx System Generator for its implementation on FPGA. Firstly, the generic particle filter algorithm is simplified to reduce calculation quantity and make it easy to implement. Secondly, the modular design is adopted, and the state machine is used to synthesize and realize the sequential control of each module. Finally, the algorithm is converted to hardware language to complete the hardware simulation. The simulation results show that: each module of the simplified particle filter algorithm functions properly and the algorithm has a good tracking accuracy and running speed, which can be used in the implementation of the particle filter in non-linear and non-Gaussian systems. It provides a reference for the hardware implementation of particle filters.