Abstract: In the reserve model of B-F, in order to make the estimated reserve of the accident year mean independent of the specific form of prior distribution, the credibility method is adopted. On the basis of \ncite10 model, considering the relationship between the amount of claims in different years of progress in the same accident year, the optimal non-homogeneous and homogeneous credibility estimates of the accident year means are obtained under the balanced loss function. When \omega=0, the result is consistent with that of the original model, and the original model is generalized.