The invention relates to a maturity degree evaluation method and system of a power selling market. According to the method, firstly, evaluation parameter samples and evaluation target quantity samplesare acquired, the acquired samples are utilized to calculate correlation degrees between evaluation parameters and an evaluation target quantity, then the correlation degrees are utilized to screen the evaluation parameters, an effect of utilizing only evaluation parameters of high correlation degrees with the evaluation target quantity to evaluate the evaluation target quantity is realized, a calculation amount is reduced, and precise evaluation can also be realized for the evaluation target quantity. Finally, according to the method, the evaluation parameters which are of the high correlation degrees and obtained by screening are utilized to calculate a score of the evaluation target quantity, and precise evaluation for the evaluation target quantity is realized, that is, comprehensiveand precise evaluation for a maturity degree of the power selling market is realized.