The invention discloses an FPGA logic testing structure and method. The FPGA logic testing structure includes an FPGA module, an external storage module and a control module, wherein the FPGA module provides internal signals to be tested or variables of the FPGA; the external storage module is connected with the FPGA module and performs storage processing on the internal signals to be tested or variables of the FPGA module; and the control module is connected with the external storage module, selects the stored signals to be tested or variables, completes external reading, determines the internal logic running state of the FPGA module and then displays the internal logic running state of the FPGA module. Compared with the prior art, the FPGA logic testing structure and method can conveniently and efficiently track and observe the signals to be tested, can verify internal logic of FPGA, can greatly improve the efficiency of the initial stage and debugging stage of the project, are low in occupancy of resources, can reduce the development cost relative to a special instrument, have high practicability, are wide in the application range, and are easy for popularization.