The dynamic fragmentation of ZrCuNiAl bulk metallic glass (BMG) subjected to various impact velocities was investigated in argon atmosphere. The results demonstrated that the ZrCuNiAl metallic glass generated debris after impact. The cumulative mass distribution curves of ZrCuNiAl BMG samples after impact under various velocities were obtained; the results showed that the cumulative mass of BMG samples conforms to the Schuhmann power function distribution. The characteristic fragment size lambda governing the fragment distributions was determined by fracture toughness and expansion strain rate. The results demonstrated that characteristic fragment size decreases with an increase in impact velocity, which was well described by the model. A relationship between the cumulative mass distribution and the impact velocity of Zr55Cu30Ni5Al10 alloy was obtained based on energy principles. This formula is feasible to predict the cumulative mass distribution of Zr55Cu30Ni5Al10 alloy after impact under a wide velocity range.