Abstract: To study the relationship between the detonation velocity and size of channels charged with superfine insensitive HMX, the explosive circuit was designed, and the test method of detonation propagation velocity established. By testing and analyzing the detonation velocity of different channel charges, the limiting detonation velocity and limiting size of the charge under test were obtained. Through them, an empirical correlation and semi-experimental equation of detonation velocity and charge size were obtained. They are useful for the application of superfine insensitive HMX in initiating devices.