A method for improving OpenCL hardware execution efficiency described in this invention comprises the following steps: compiling a kernel implemented in OpenCL, generating Verilog code with a high-level synthesis tool; analyzing the interfaces of auto-generated Verilog code, recording signals, timing sequence, and function of the interfaces; manually modifying and optimizing the Verilog code; inserting a file replacement command in the script responsible for flow control, replacing the auto-generated code with the optimized Verilog code; rerunning OpenCL compiler and generating an ultimate FPGA configuration file. The invention makes manual optimization of the auto-generated Verilog code becomes possible, by parsing the compilation flow of OpenCL environment and analyzing the structure and interfaces of the auto-generated Verilog code. It promotes the performance of kernels, by increasing working frequency, achieving more parallelism and taking full advantages of FPGA hardware resources, and improves the execution efficiency of OpenCL on FPGA platform significantly.