based on the technical requirement for the gradient dispersing of fragments with small mass and high charge-weight ratio, this paper performs simulating calculation and theoretical analysis on the structure of gradient dispersing fragments whose driving energy comes from dispersion charge, proposing a theoretical calculation formula for the initial dispersing velocity of fragments with small mass and high charge-weight ratio. A plan for gradient dispersing fragments of single layer is designed, and then a ground static ejection test is conducted. The relative error between initial velocity of gradient dispersing fragments gained from test and that gained from theoretical calculation is 3.34%. This paper refers to results of the designed plan above and applies them to a principle prototype, then performs a ground static ejection test. The relative error between initial velocity of gradient dispersing fragments of multiple layers gained from test and that gained from theoretical calculation is 6.06%. These results demonstrate that the initial dispersing velocity from theoretical calculation model is consistent with that from fragments of principle prototype, and the relative error is 6.06%; the theoretical calculation formula can be a good instruction to the research and development of gradient dispersing products like fragments with small mass, high density and high charge-weight ratio.