As the fundamental building block of composite materials，the mechanical properties of carbon fiber tows play a critical role in material design and engineering applications.To address the issues of variability and dispersion in tow performance，this study conducted fundamental mechanical tests，including tensile strength， tensile modulus， and elongation at break.The test data from three different manufacturers were systematically analyzed using the recommended statistical method of single-environment B-basis values， aiming to comprehensively evaluate the mechanical properties of carbon fiber tows and provide a reliable basis for material selection. The analysis showed that the tensile properties of the tows from all three manufacturers followed a normal distribution，meeting the basic assumptions of statistical analysis.The B-basis statistical results indicated some differences in performance parameters among manufacturers，yet all fell within acceptable engineering ranges，demonstrating adequate application reliability.As a conservative estimate of the lower bound of material properties， the B-basis value effectively reflects the performance characteristics of carbon fiber tows and offers an engineering-relevant reference for the selection and application of composite materials.