For researching the relationship between the ranges and the range angles of certain type large caliber cartridge, research it with the way of solving exterior ballistic. Giving the movement cartridge controlling equations under right angle reference systems, which takes t as the independent variable, and also sets up its model based on MATLAB\SIMULINK software, then calculates the ranges which belongs to the range angles range 50°～55°, drafts the curve relation between the ranges and the range angles. Calculate the range angles in different muzzle velocities, and also draft the curve relation between range angles and muzzle velocities. From the curve, it shows that the maximum range angle is increased when muzzle velocity is higher. The test result shows the method is convenient and easy.