Objective To analyze the clinicopathological characteristics and prognosis of patients with low HER2 expression and explore the prognostic factors. Methods The clinicopathological and prognostic data was collected from the HER2 negative breast cancer patients who were admitted to Mianyang Central Hospital. The patients were divided into 3 groups, Including HER2(0), HER2(1+) and HER2(2+). The differences in clinicopathological features, overall survival (OS) and disease-free survival (DFS) of the three groups were compared, and the prognostic factors of HER2 low expression breast cancer were analyzed by the univariate and multivariate Cox proportional hazard regression. Results In the overall cases, there were statistical significances in the difference of N stage(P<0.01) and HR(P<0.01) between the three groups. In the HR+ subgroup, there was statistical significance in the difference of N stage(P<0.01) between the three groups. In the HR- subgroup, there was no statistical significance in the included indicators. There was no significant difference in the OS and DFS between the three groups. The multi-variate analysis results by Cox proportional hazards regression found that the HER2 low expression breast cancer patients with T2~4, N1~3 and Ki-67>14% had higher risks of DFS shortening(P<0.05), and the low HER2 expression breast cancer patients with T2~4 and N1~3 had the higher risks of OS shortening(P<0.05).Conclusion The HER2 low expression breast cancer patients have the higher N stage and more HR+, however, there is no significant difference in the OS and DFS be-tween HER2(0) and HER2 low expression breast cancer