Abstract: For the field programmable gate array (FPGA) based beamforming algorithm of multi-beam sonar in frequency domain, the coordinate rotation digital computer (CORDIC) algorithm is usually required to generate the weighted coefficient in real time, but for large number of beams and broadband signal, a lot of hardware resources would be consumed. An improved real-time weighted coefficient generation method based on CORDIC is proposed in this paper. By frequency point multiplexing, multiple beam banks can share the same CORDIC IP core to generate weighted coefficients in real time, which reduces CORDIC resource consumption by 87.5%. By introducing the idea of two-dimensional ping-pong and throw after use, the ping-pong processing of the weighted coefficient cache RAM based on beam and frequency point multiplexing can reduce the occupancy of RAM storage space by 95.3%. This improved method saves a lot of CORDIC resources by occupying a small amount of RAM storage space and balances the consumption of RAM and CORDIC resources, and has good engineering application value.