This study explores how emotional appeals-based public service announcements (PSAs) intrigue people’ emotions and how these emotions affect their subsequent motivation and donation intentions. Results show that PSAs of positive appeals induce positive emotions, whereas PSAs of negative appeals and of a combination of negative and positive appeals elicit negative emotions. However, the latter tends to be less than the former one. Further experimental results reveal that negative emotions affect the subsequent donation intentions via the mediator motivation, however, in different ways. Subjects who under negative emotions tend to be trigued altruisitic motivation, however, when the level of negative emotions raise, egostic motivation would be induced because subjects need it to relieve the distress brought by the too intensed negative appeals.