 This is a community-based participatory research aiming at helping the only-child loss parents to be happier and resilient from bereavement. It is a psycho-behavioral intervention research. There are two intervention programs in this study. One is derived from a foreign psychotherapy, developed by an American psychologist and has been testified the effectiveness in promoting happiness. Another one is developed by the researchers based on the previous cross-sectional survey and interviews with those bereaved parents. The researchers will apply randomized controlled trial to testify and compare those two intervention programs in a Chinese community. 