The invention relates to a small sample relay protection reliability parameter estimation method based on a SVM (Support Vector Machine). The method comprises the following steps: 1, using an empirical formula to calculate the empirical reliability of an original failure sample and performing linear processing; 2, using a SVM algorithm to perform regression of failure data and performing prediction to generate a new enlarged sample; 3, performing linear fitting of the original failure data to obtain a parameter estimation value as a new iteration initial value; and 4, performing least square fitting of the enlarged new sample to obtain a final reliability parameter estimation result. Compared with the prior art, the method provided by the invention can effectively solve problems that priori knowledge and statistical samples are extremely in shortage as the operation time of an intelligent transformer station is short, and is beneficial for objective analysis and evaluation of reliability of a protection system.