On evaluating the hitting precision of a missile which throws sub-missiles, it is a key question to estimate the normal distribution parameter of the sub-missile dispersion center. The usual method is, to find a sub-missile disper firstsion center first from each group data of the sub-missile's falling point coordinate, then to estimate the parameters according to a few data of dispersion center using the classical statistic method. Its shortcomings are the high probability to make a wrong conclusion. Considering that the sub-missile dispersion center, which cannot sufficiently express the information contained in the sub-missile falling point data group, is only its first moment, in this paper a new method on fusion estimating the distribution parameter is researched.