具有不可预测性的随机数是保证保密通信的关键因素。通过输入单比特量子态，基于量子行走的演化，制备了多路径相干叠加态，并通过一次量子测量，得到了多比特随机数。详细计算了输入状态、精确调控的演化过程以及演化步数对多比特量子纯态随机性的影响。对于目前的单光子探测技术，量子行走为随机数产生率的提升提供了很好的平台。

Unpredictable random numbers is the key to ensure the security of quantum communication. We discuss the multi-bit random number produced by the evolution of a quantum walk via the single-bit input, the preparation of multi-path coherent superposition state, and single quantum measurement. We have investigated in detail the influences of input state, precisely engineered evolution and number of evolution steps on the randomness of multi-bit quantum pure states. As for the current single-photon detection technology, quantum walks provide a good platform to increase the generation rate of random numbers.