Objective To explore the fatigue development trajectory and influencing factors of postoperative patients with acute myocardial infarction（AMI）. Methods From December 2019 to January 2021,206 patients with first AMI in the cardiology department of a tertiary hospital in Huzhou were selected by convenience sampling method. The multidimensional fatigue scale-20 was used to investigate the patient’s fatigue level on the second day after admission and 1,2,4 months after discharge,and the latent class growth model and single factor analysis were used for data processing. Results It is recognized that the fatigue trajectory of AMI patients is divided into 3 potential categories,namely,the obvious improvement group（15.2%）,the slow remission group（62.8%）,and the continuous fatigue group（22.0%）;single factor analysis shows that the 3 trajectory categories are different with statistical significance in gender （χ²=29.384,P<0.001）,marital status （χ²=6.774,P=0.034）,number of comorbidi-ties（χ²=27.131,P<0.001） and cardiac function classification（χ²=20.416,P<0.001）. Conclusion The fatigue of most patients with AMI can be improved within 4 months from acute admission to discharge. There is group heterogeneity in fatigue trajectory. Medical staff should formulate staged and specific full-course nursing interventions according to different trajectory categories.