A randomized controlled trial was conducted to evaluate the effectiveness of group-based positive psychotherapy on psychological resilience, depression, well-being, sleep quality, dehydroepiandrosterone in only-child-lost people. A total of 80 only-child-lost people who met the inclusion and exclusion criteria were expected to recruit. There were six weeks in the intervention, including positive introduction, positive reaction, gratitude, meaningful, three good things, and using personal strength. The measurements were conducted at the baseline, immediately after the intervention, 3-month after the intervention.

Inclusion Criteria:

1. having only one child or legally adopting;
2. No surviving children;
3. basic language expression and comprehension skills;
4. the score of Connor-Davidson Resilience Scale is lower than 82

Exclusion Criteria:

1. in the acute bereavement period (<6 months);
2. unable to participate in activities due to severe physical illness;
3. having diagnosis of sever mental illness;
4. receiving other psychological therapy.

The intervention provider, investigator, and outcomes assessor have not been informed of the group allocation, but the participants may be aware of the group allocation because of the nature of the research design.