The work aims to analyze the impact of typical 8 g tungsten alloy fragments on the ballistic limit (V50) of a 15 mm Q235 steel target. The accuracy of the simulation model was verified through ballistic gun tests, and then the numerical simulation method was employed to study the effects of different shapes, masses, and landing angles on the penetration law of 15 mm Q235 steel targets. The V50 of both square and spherical fragments decreased with the increase of fragment mass. For penetration through a 15 mm Q235 steel target, the V50 of the square fragments was lower than that of the spherical fragments. As the mass of the fragments increased, the difference in V50 between the two types of fragments gradually decreased. On this basis, the relationship between the diameter of square tungsten alloy fragments penetrating the target plate and the penetrating energy was obtained through dimensional analysis. The error between the calculated formula value and the simulated value was within 10%. The conclusion is that the effect of 8 g tungsten alloy fragments on the V50 of a 15mm Q235 steel target has important reference significance for the selection of fragments.