According to game theory, a mechanism of altruistic behavior based on reputation and future expectation is proposed in this paper. In this mechanism, “Reputation” is used to evaluate the historical behavior of one player and predict the probability of the player choose cooperation. Players tend to choose the one with higher reputation as their opponent. The total payoff consists of current payoff and futurepayoff. Analysis and simulations show players choose cooperation voluntarily for the purpose of payoff-maximizing. The reputation oscillates with a particular mode in a specific domain of convergence. The higher the future expectation is, the greater the possibility of cooperation emergence will be. The level of convergence average reputation of the group relies on the level of initial average reputation of the group. In addition, the non-subjective factors exist in the real world a resimulated. A slight increase of the non-subjective factors can effectively reduce largely the average convergence reputation of the group. These factors seriously prevent the cooperation from emerging.