Abstract: This design is based on the open source soft-core processor OR1200 with its unique instruction set.With the modification to the interior core module of the CPU,a new instruction is built as l.cp.Through calling the instruction,CPU triggers a co-processor,meanwhile sends data and op-code to it.By the same time,CPU suspends its own instruction pipeline.After finishing sequential data processing,the co-processor stops the BUS occupation,which resumes the suspended pipeline.The co-processor realizes GO-CFAR algorithm.And the corresponding simulation result verified the design.