Accurate and quantitative prediction of coal caving gas emission was one of the important contents of mine gas emission prediction. The current prediction formula of gas emission rate in coal caving mining did not fully consider the mining parameters and gas seepage process in coal block, which leaded to the prediction accuracy of gas emission rate in coal caving mining.Based on Darcy seepage theory, taking the actual gas parameters of 5301 coal face of Sihe Coal Mine as the data source, the mathematical and physical model of coal block gas seepage and emission was constructed. Based on the UDS interface of fluent, the gas emission process of coal blocks with different sizes and shapes was simulated, and the general calculation formula of gas emission rate of coal blocks with equivalent radius, surface area volume ratio and time as independent variables was established by numerical analysis method. Combined with the actual mining coal transportation process and mining coal cutting process, considering the distribution of mining coal geometric parameters, the mathematical modeling method was used to build the calculation model of coal mining coal gas emission and the calculation model of coal mining coal gas emission. The gas emission data of 5301 working face in Sihe coal mine were measured, and the relative error between the calculated results and the measured results was 10.96%.The research showed that the calculation model had a certain field practicability.