Aiming at the problem of using SD card to realize high speed and large capacity data storage,a SD card controller based on FPGA is designed.At present,SPI mode is mainly used when microprocessor-driven SD card is used,but the storage speed of SPI mode is low.In order to realize high-speed and large-capacity data storage,it is necessary to develop an SD card controller based on SD mode.In this design,FPGA is selected to design the controller,which is mainly divided into clock frequency division module,command response module,data transmission module and CRC check module.The FPGA part of ZYNQ7010 chip is used for simulation verification of each module,making full use of the expansibility of FPGA and SD mode storage speed advantage.It can provide support for high-speed and large-capacity data storage using SD cards.