A reliability evaluation method for P-T curve based on multi-sample time series analysis is proposed.The method can synthesize longitudinal and transverse information existing in performance curves

and evaluate the internal ballistic reliability of solid rocket engine with high precision.The maximum likelihood estimations of multi-sample time series with both equally and unequally spaced data are discussed in detail.Furthermore

the formulas of point estimation and confidence interval estimation are introduced when upper and lower limits of P-T curve are assumed.An example is presented.