FLASH is called flash memory, also known as highperformance non-volatile memory. It combines the advantages of RAM and ROM which can transfer data quickly and maintain data for a long time in case of power failure. This is why many portable digital devices select flash memory as a storage medium. In recent years, the role of flash memory in the embedded field has become increasingly important. In view of the existing problems of FLASH, including slow erasing, difficult data tracking, complicated operation commands and timing, this paper proposes a method of realizing analog SPI + FLASH system based on FPGA which takes advantage of the parallelism, reconfiguration, high real-time and fast speed. In this paper, the DE10 development board of ALTERA company is used to simulate MX25L3206E chip (SPI+FLASH system) with Verilog Hardware Description Language and finite-state machine on QuartusII development platform. Thus, an integrated system platform based on FPGA simulation SPI+FLASH and controller is established, which replaces the function of actual SPI+FLASH. The main work includes decoding operation commands and accurately controlling FLASH work, designing interface timing and control logic, and data transmission with dual-port RAM. Then STM32 is used to simulate the host MCU to send data and instructions to the FLASH system simulated by the FPGA through the SPI interface. Finally, the real-time signal is captured and displayed by using the tool software of Signal TapII Logic Analyzer to achieve the purpose of the system function test.