Abstract: The rate sensitivity of concrete strength is one of the important scientific problems in the field of concrete mechanics. The existing prediction methods for the dynamic increase factor of concrete are still mainly based on the data fitting model, and the fitting parameters usually have no actual physical significance, thusly it cannot relate to the mechanism interpretation of the concrete rate sensitivity. This paper takes the tensile strength of concrete as the research object. Based on the basic concepts of self-consistent finite stress model and on Newton's law of motion, derived and established is the mathematical equation of a dynamic increase factor which can reflect the strain rate effect mechanism of concrete. Based on a fib specification model and a J criterion model, proposed is a semi-analytical and semi-empirical analysis method to analyze the dynamic increase factor of concrete tensile strength. Through the case analysis based on mesoscopic numerical tests and the comparison based on the test data in the literature, it is verified that the analytical model revised can effectively reflect the real physical law of the dynamic increase factor of concrete tensile strength.