The invention relates to a field programmable gate array-based (FPGA-based) realization method for converting a liquid crystal display (LCD) signal to a video graphics array (VGA) signal, which belongs to the technical field of the FPGA design, and a system is mainly established by an FPGA module, a synchronous dynamic random access memory (SDRAM) module and a register-packs network module. The FPGA module is used as a core of a conversion system, consists of a clock management module, a resetting module, an LCD signal receiving module, a writing first-in first-out (FIFO) module, an SDRAM controller module, a reading FIFO module, an FIFO controller module and a VGA display module and is realized through a Verilog hardware description language (HDL) code; the SDRAM module is a cache for processing the data of the FPGA module, and a controller of the SDRAM module is realized inside the FPGA module; and the exclusion network module is formed by register packs and used for converting a digital signal to an analog signal. The FPGA-based realization method has the advantages of low cost, short development period, low development risk, convenience in modification design and good confidentiality.