The invention discloses a self-service capacity expansion method based on a correlation coefficient criterion. The method comprises the following steps: S1, initializing parameters, and setting a correlation coefficient threshold value rho epsilon, a positive integer M, a self-service sample capacity B and an equal fraction m of a histogram function; S2, copying a new sample, generating a positiveinteger R-U (0, M) obeying uniform distribution randomly, calculating a remainder p = mod (R, n), wherein n is the sample capacity; S3, calculating the mean value of the copied samples, if the ith new sample is the ith new sample, repeating S2 to obtain a group of copied samples, calculating the mean value of the copied samples; S4, obtaining self-service resampling samples, and repeating the steps S2 and S3 to obtain the similarity rho (f (x))) of the self-service resampling samples to calculate the resampling samples and the original samples; f (x *)) if rho (f (x); and if f (x *) is greater than or equal to rho epsilon, outputting a resampling sample, otherwise, repeating the steps S1 to S4 until a similarity condition is satisfied. The resampling sample obtained by the method fully utilizes the information of the given sample, and the obtained resampling sample is closer to the real situation.