In order to establish spray break-up model of multi-hole injection on gasoline direct injection engine, Huh Gosman model was analyzed and evaluated. The primary break-up particle size distribution formula was built based on injection pressure. The spray break-up model was built for gasoline direct injection in cylinder. Finally, by establishing the capacity spray experiments, gasoline free spray experiments were carried out to verify the rationality of the model. It is found that estimating initial droplet size by experience formula to evaluate second break-up model, the spray penetration calculated with Huh Gosman model is smaller than experimental results. Through establishing primary break-up particle size distribution formula and modifying Huh Gosman model, the simulation results and the practical results are close to each other. At last, free spray under different injection pressure were simulated with above established models. Results matches well with the experimental results and the maximum average error is less than 5%.