The invention provides a material strength distribution obtaining method. The method comprises the steps of obtaining multiple material strength samples defined in the specification through a materialstrength test, and determining test data-based strength random variable samples defined in the specification; expanding a strength random variable eta by adopting a chaotic polynomial, and accordingto Gaussian sampling, performing calculation to obtain all-order chaotic polynomial basis function samples defined in the specification; by adopting a Markov chain-Monte Carlo algorithm, obtaining posteriori distribution samples, defined in the specification, of all-order chaotic polynomial coefficients gamma; according to the reconstructed chaotic polynomial coefficient samples defined in the specification and the chaotic polynomial basis function samples defined in the specification, determining posteriori distribution samples, defined in the specification, of the strength random variable; and according to the posteriori distribution samples, defined in the specification, of the strength random variable, calculating posteriori distribution samples, defined in the specification, of strength, and finally obtaining material strength distribution by adopting an interval statistics method. According to the method, the material strength distribution can be obtained by only finishing few strength tests, without assuming a material strength distribution type, so that a large amount of test time and expenditures are saved, and meanwhile, an error caused by wrong selection of a material strength distribution model is avoided.