The invention discloses an SPI FLASH controller based on an FPGA and a design method of the SPI FLASH controller and relates to the field of computer chip design, and a marker register is configured according to the SPI FLASH instruction type software; a plurality of logic core FIFO, a state machine FSM and an SPI time sequence generation module are arranged in the FPGA; the FIFO receives the values of the register and sends the values to the state machine, and the state machine decides to read corresponding FIFO according to the content of the marker register; data read from the FIFO are converted into SPI time sequences, and the SPI time sequences are output to the SPI FLASH through an SPI interface. The state machine receives the reading return information of the SPI FLASH and caches the information to the FIFO to be read by software. The SPI FLASH controller is based on the FPGA logic design, the SPI FLASH controller is realized autonomously, the implementation method is simple, the system complexity is reduced, extra FPGA IP is not required to be purchased, and the project cost is reduced greatly.