Abstract: The statistical analysis of the strength data of T300/QY8911, T300/HD03 and T300/QY8911-Ⅱ gives the maximum standard deviation. And it is shown that the strength performance scatter of the unidirectional composite laminate in 0° or 90° stacking sequence is bigger than that of the multidirectional laminates. From the statistical distribution test of the strength performance of T300/QY8911, T300/HD03 and T300/QY8911-Ⅱ, it is also found that the strength performance of these composites follows the log-normal distribution. Then a small sample factor method with high precision for the reliability design of composite strength performance is presented, and is compared with two other methods. The verification results show that this method presented in this paper can give the stable calculation results and is with high calculation precision. Moreover, it can obtain the bigger prediction values than the other methods, and more sufficiently make use of composites, so as to save specimens.