Adolescence is a critical period for the moral development of individuals, which has the practical characteristics of rapid learning ability in all aspects, quick and active thinking, but accompanied by physical and psychological immaturity, and easy to be affected by undesirable phenomena. Teenagers are becoming more and more closely connected with the Internet, and the negative impact of the Internet on the moral development of adolescents is gradually exposed. As the highest level of moral behavior in the network, altruistic behavior on the Internet has high requirements for the moral cognition, moral emotion and moral will of the actors, and it is also the action guide for teenagers to shape a complete moral system. Therefore, it is necessary to give full play to the strength of all parties to help young people establish moral cognition, enhance moral feelings, strengthen their sense of moral responsibility, consciously make online altruistic behaviors, and continuously inject fresh blood into creating a clean and upright online environment.