The belief function theory can effectivelymodel the belief induced by uncertain evidence. Withinits framework, when new pieces of evidence are available,belief is revised by Dempster rule of combination. Sincethe Dempster rule cannot determine the weight of focusing downwards and would lead to a counterintuitive resultfor combining high conflicting beliefs, its applicability isrestricted. A large number of alternative rules have beenproposed to solve these problems. We suggest some properties that a good rule should possess, and then a newrule is presented in this paper. This rule can determinethe weight of focusing downwards according to focal elements' cardinalities, and redistribute incompatible beliefmass proportionally to the subsets involved in the combination. The properties of our rule are clarified and comparedwith those of some other rules through several numericalexamples, which shows its superiority.