Objective To investigate the application of behavioral change theory-based intervention in obese polycystic ovary syndrome. Methods A total of 70 patients with obese polycystic ovary syndrome admitted to a hospital in Xiamen from January 2019 to April 2021 were selected as subjects and assigned to a control group（n=35） and an experimental group（n=35） using random number table method. Patients in the control group received conventional nursing intervention

while patients in the experimental group received behavioral change theory-based intervention after receiving conventional nursing

and both groups received consecutive intervention for 2 months. The dietary intake behavior and follicle development volume

follicle number

endometrial thickness

quality of life

anxiety and depression of the patients in the 2 groups were compared before and after the intervention. Results The dietary intake behavior scores after the intervention were higher in both groups than before the intervention

with scores in the observation group higher than those in the control group

and the differences were statistically significant（P<0.05）. The follicle development volume after the intervention in the experimental group was smaller than that in the control group

and the number of follicles in the experimental group was smaller than that in the control group

and the differences were statistically significant（P<0.05）. The scores of self-care ability

physical status

mental health and social function scores after the intervention in both groups were higher than those before the intervention

with scores in the experimental group higher than those in the control group

and the differences were statistically significant（P<0.05）. The Self-rating Depression（SDS） and Self-rating Anxiety（SAS） scores of patients after the intervention in the two groups were lower than those before the intervention

with the experimental group having lower scores than the control group

and the differences were statistically significant（P<0.05）.Conclusion The behavioral change theory-based intervention can effectively improve the eating habits

ovarian function

quality of life and negative emotion in patients with obese polycystic ovary syndrome.These advantages justify a wider application of this intervention clinically.