Abstract: In order to reduce the test cost for obtaining the design allowables of composites, a regression analysis-based B-basis value statistical method merging multiple condition samples which was latest issued by Composite Material Handbook-17-G was introduced, and the rationality and applicable conditions for the addition of engineering experience judgment in the check of variation between batches, the equality check for square deviation between condition samples and the normality check were expounded emphatically. Then, the software for statistical analysis of B-basis value was developed based on the merging method of multiple condition samples. Finally, the software was used to statistically analyze the mechanical properties data of partial Jiangsu Hengshen Company Limited composites. The results show that comparing with the traditional single condition sample statistic program, the multiple condition samples merging method not only raises the B-basis value significantly, but also overcomes the limitation for number of samples and number of batches in traditional statistic program. The conclusions obtained show that this method has higher operability, and is applicable to the statistical analyses for B-basis values of composites in the case of reduced sample.