The reliability evaluation of aviation support special equipment is faced with the problem of insufficient failure sample data.In order to evaluate the reliability of small samples more accurately,the improved average rank method was used to calculate the empirical distribution function of samples,and a three-parameter Weibull distribution estimation method was proposed based on GM-SVR.In this method,the advantages of grey model (GM) in location parameters and the good effect of support vector regression (SVR) in small samples were used to accurately estimate the three parameters of Weibull distribution.The simulation experiment for the model was carried out using MATLAB toolbox.The results show that the GM-SVR method has higher parameter estimation accuracy than the traditional probabilistic statistical method when the fault data samples are small.Taking the jet deflector as an example,the shape parameter,scale parameter and position parameter of Weibull distribution were calculated,the correlation coefficient was 0.995 3,and the root mean square error was 0.038.It proves that the GM-SVR method has good fitting accuracy in the case of small samples,and can be used to accurately evaluate the reliability of special aviation support devices.