The invention disclosers a four-way full-high-definition video processing circuit based on a field programmable gate array (FPGA). The circuit comprises an FPGA chip. The FPGA chip comprises a storage controller, a channel selection switch module, a first video layer overlaying module, a second video layer overlaying module, a third video layer overlaying module, a fourth video layer overlaying module, a video time sequence control module, a video composition module, a video mode parameter controller, four video input processing modules and four video amplifying modules. The picture-in-picture and picture-out-picture video processing circuit based on the FPGA chip is utilized, the requirements for collecting multiple ways of full-high-definition video signals simultaneously are met, and the circuit further has the advantages of being simple in structure, easy to design and achieve and the like. The four-way full-high-definition video processing circuit based on the FPGA can be widely applied to the field of high-definition video processing.