Abstract: Objective To explore the positive feelings of the primary caregivers of cancer patients and their relationship with adult attachment and social support. Methods A total of 200 primary caregivers of cancer patients from a Third Grade Class hospital of AnHui Province were investigated with General Information Questionnaire, Positive aspects of caregiving, Experiences in Close Relationships Inventory, Social support rating scale from January to December 2017. Results A total of 200 questionnaires were distributed and 190 valid questionnaires were recovered, with an effective recovery rate of 95.0%. The scores of positive feelings, attachment anxiety, attachment avoidance, social support were (34.04±7.64), (72.09±14.92), (47.67±16.13) and (41.51±7.43), respectively. Partial correlation analysis revealed that positive feelings had positive related with attachment anxiety, social support (r=0.188-0.368, P<0.01), and had negative related with attachment avoidance (r=-0.239, P<0.01). The multiple linear regression revealed that attachment anxiety and social support can positively predict the positive feelings of caregivers. Conclusion Health professionals should be based on attachment theory and influencing factors of positive feeling, build appropriate intervention strategies to enhance caregivers' positive feeling and improve care quality.