At the long-distance quantum key distribution(QKD) experiments,high-speed quantum transmission is needed.In this paper,quantum transmission rate at 500 Mbit/s is fulfilled based on SER/DES module inside FPGA,and a time synchronization design between transmitter and receiver using a low frequency sync-pulse(2 MHz) is proposed.For the experiment′s requirements,signal discriminator,pseudo-random number generator,time synchronization and data coding are developed.This design has been applied success...