Objective To observe the effects of cardiorenal syndrome type 1(CRS1) of different severity on in-hospital mortality in patients with acute myocardial infarction(AMI). Methods A retrospective analysis was conducted of 2094 AMI patients in the Cardiovascular Center of Beijing Friendship Hospital Database Bank. The clinical data were collected for analysis, including demography, biochemical examination, previous medical history and treatment after admission. According to the heart and kidney function, patients were classified as mild, moderate and severe. The relationship between different severity of CRS1 and AMI in-hospital mortality was evaluated. Kaplan-Meier survival analysis and Cox proportional hazard regression were used to assess the effects of CRS1 of different severity on AMI in-hospital mortality. Statistical analysis were performed using SPSS statistics 22.0. Results The all-cause in-hospital mortality increased in AMI patients as CRS1 aggravated (P<0.001). Kaplan-Meier survival analysis showed that the cumulative survival rate in CRS1 group was lower than that in the non-CRS1 group (P<0.001) and decreased with the severity of CRS1 (P<0.001). CRS1 occurrence was an independent risk factor for in-hospital death in AMI patients (RR=4.233,95%CI 2.013-8.901; P<0.001). Conclusion The presence of CRS1 adversely affects the prognosis of AMI patients. The risk of in-hospital death increases with the severity of CRS1.