Abstract: Objective: To explore the current status of happiness and influencing factor of elderly people under homebased care in Beijing. Methods: Information of happiness and influencing factors of 215 old adults in 2 Beijing communities was collected using questionnaire survey. Results: The total score of the happiness of old adults was (33.90±10.62). The score of positive affection and negative affection were (7.47±2.82) and (2.44±2.80), positive experience and negative experience were (8.93±3.60) and (4.06±3.47). The happiness of old adults was positively correlated with number of children and intelligent level. Factors influencing the happiness feeling included mental health, the energy of the elderly, physiological functions and general health. Conclusion: During the care process for old adults, care givers should pay attention to the psychological health,psychological health and the spiritual needs of the elderly, prevent brain function decline, and enhance the happiness of the elderly.Their children should give them more respect and support to increase the subjective happiness of the elderly.