对物理随机码发生器的物理参量与其产生的随机码序列的随机性关系进行了分析．根据量子保密通信对随机码序列的随机性的要求，分析了常见的随机码发生器产生的随机码的随机性，给出了利用随机高斯噪音经比较器产生随机码的随机码发生器的随机性公式．

The absolute security of quantum cryptography system was guaranteed by two aspects: no eavesdropping channel and no repetition true random codes. The randomicity of physical random number generator based on Guass noise was discussed. The relation of its correlation coefficient and entropy with the physical parameter were calculated and how to get the best performance was discussed. It is useful for developing the true random number generator used in the quantum cryptography systems.