目的　了解氰化钾 (KCN)对人精子线粒体内细胞色素氧化酶的阻断作用。方法　用不同浓度的 KCN作用于活力正常的精子 ,阻断精子内细胞色素氧化酶的活性 ,观察其活性被阻断的情况。结果　低至 8.3× 10 - 3mol/L 的 KCN即可完全阻断精子内的细胞色素氧化酶。结论　实验结果提示 ,8.3× 10 - 3mol/L 的 KCN可能是阻断精子线粒体内细胞色素氧化酶活性的最低浓度。 Objective To understand the blocking effect of potassium cyanide (KCN) on cytochrome oxidase in human sperm mitochondria. Methods Different concentrations of KCN were applied to normal viable sperm to block the activity of cytochrome oxidase in spermatozoa and to observe its activity was blocked. Results as low as 8.3 × 10 - 3mol / L of KCN can completely block the intracellular sperm cytochrome oxidase. Conclusion The experimental results suggest that KCN of 8.3 × 10 -3 mol / L may be the lowest concentration of cytochrome oxidase activity in mitochondria of sperm.