水是影响尾矿库稳定性的最主要因素之一。对青海云天化磷石膏尾矿库进行了洪水条件下的防洪和渗流计算，并利用上述计算结果对其稳定性进行了计算分析。在计算过程中，针对磷石膏尾矿库的特殊性，提出了将防洪计算和渗流计算紧密结合起来的一种计算思路。结果表明，该尾矿库在其防排渗设施正常运行的工况下是安全的，但在其排渗设施失效的情况下则是不安全的，在实际运行中应当加强对排渗设施的监测与维护。

Water is one of the most important factors on the stability of tailings pond. The flood calculation and seepage calculation on the Yuntianhua phosphogypsum tailings pond are carried out under flood conditions, then the results are used for the stability calculation. In the calculation, considering the particularity of the phosphogypsum tailings pond, a revised scheme which combines the flood calculation and seepage calculation together is put forward. The results indicate that the tailings pond runs safely when the seepage-proofing and drainage facilities operate normally, but when the drainage facilities become invalid, the tailing pond is unsafe. The monitoring and maintenance of the drainage facilities should be strengthened in the actual operation.