Abstract: Objective To explore the relationship between insulin-like growth factor 1 and breast cancer by understanding the level of human Growth Hormone and insulin like growth factor 1 (IGF 1) of breast cancer patients.Methods A 1:1 age matched case-control study was used.In all, 197 breast cancer patients and 197 control women were collected.The general information, growth hormone, and insulin-like growth factor 1 levels of the two groups were analyzed.Results There was no statistically significant difference in the growth hormone levels between the two groups (P>0.05).There was a statistically significant difference in the insulin-like growth factor 1 of women under 50 years old between the breast patients and the control group (P<0.01), and there was no statistically significant difference in that of women over 50 years old between the two groups (P>0.01).The results of Logistic regression analysis showed that β=0.137, OR=1.147 (P<0.01).Conclusion The higher level of insulin-like growth factor 1 is a risk factor for breast cancer.It may be used as one of the indicators of breast cancer screening.