In order to further study the motion laws of the particle on the semi-cireular orbit,the whole motion ofthe small ball as a particle,from the entrance of a vertical and smooth semicircle inner track to the landing point ,isdiscussed.By mathematical method ,the dimensionless conditional factor related to the initial velocity is delined .andthe conditional factor is used as the independent variables to analyze the four phvsical quantities -the motion timefor the ball to adhere to the track ,the fight time in the air , the maximum rising height and the maximum horizontarange.Analysis reveals that under all possible values of initial velocity, the expressions for these four physicaquantities are all related to the conditional factor.This mathematical analysis provides a detailed deseription of themotion laws of particles on a semicireular inner track model, and its results can offer theoretical support forteaching,research ,and applications related to the semicircular inner track model of particles.