Quantum key distribution (QKD) technology is a new symmetric key distribution technology, which uses random number to generate quantum signal at the transmitter. At present, with the continuous development of high-speed QKD technology, higher requirements are put forward for the speed and reliability of random number source. The overall requirements of high-speed QKD system random number source are summarized in detail, and the 10 Gbps high-speed random number source and real-time self-check scheme based on field programmable gate array (FPGA) are designed and realized. The random number source is realized by using the phase jitter principle. A single random number source is realized by stacking 128 ring oscillators, and then 10 Gbps high-speed random number is generated by parallelization instance. The random data can pass GM/T0005_2012RandomnessTestSpecification. Then, according to the unique use demand of QKD system for random number, areal-time self-check module of 10 Gbps processing bandwidth is designed and realized, which guarantees the reliability of high-speed random number used by QKD system and provides support for the development of high-speed QKD system.