基于中值Ｓ－Ｎ曲线的三参数幂函数式，根据极大似然原理，分别给出了测定Ｐ－Ｓ－Ｎ曲线的单点试验、成组试验和单点－成组试验结果的Ｐ－Ｓ－Ｎ曲线公式。并进行了对比试验，使用文中方法统计分析试验数据，发现单点法、单点－成组法及成组法测定出的Ｐ－Ｓ－Ｎ曲线较接近。由于单点法能够大量节省试样，且能保证一定的精度；因此它适合构件和模拟件Ｐ－Ｓ－Ｎ曲线的测定 Based on the three-parameter power function of the median S-N curve, single point test, group test and single point-group test result of P-S-N curve are given respectively according to maximum likelihood principle -S-N curve formula. And the comparative test was carried out. Using the method of statistical analysis of the experimental data, it was found that the P-S-N curve measured by single point method, single point-group method and group method was closer. Because the single-point method can save a lot of samples, and can guarantee a certain accuracy; it is therefore suitable for the determination of P-S-N curves of components and mock-ups