Objective To evaluate the diagnostic efficacy and clinical value of portable 12-lead electrocardiograph in early screening of acute myocardial infarction (AMI) in primary Chinese medicine hospitals. Methods A total of 108 patients with suspected acute chest pain who were admitted to the Department of Internal Medicine of Zhengzhou Guancheng Hospital of TCM from January 2023 to December 2025 were selected as the research subjects. All patients were simultaneously examined by portable 12-lead electrocardiograph and the hospital’s routine electrocardiograph. The clinical final diagnosis was used as the gold standard to compare the diagnostic efficacy indicators of the two devices, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. At the same time, the change of time delay in each stage before and after the implementation of the“ onenetwork ECG system” was analyzed. Results The sensitivity of portable 12-lead electrocardiograph in diagnosis of AMI was 90.4% (47/ 52), specificity was 93.6% (44/47), PPV was 94.0% (47/50), NPV was 89.8% (44/49) and accuracy was 84.3% (91/108). At the same time, the corresponding indexes of the hospital’s routine electrocardiograph were sensitivity 92.3% (48/52), specificity 93.8% (45/48), PPV 94.1% (48/51), NPV 91.8% (45/49), and accuracy 86.1% (93/108), respectively. After the implementation of the“ one-network ECG system”, the total delay time from the first medical contact (FMC) to the confirmed referral for patients was shortened from (150.0±25.3) min before implementation to (28.0±8.6) min (P＜0.01). Conclusion The portable 12-lead electrocardiograph has good diagnostic efficacy in early screening of AMI in primary Chinese medicine hospitals, and its accuracy is comparable to that of the hospital’s routine electrocardiograph. Moreover, the combination of “one-network ECG system” can realize remote real-time diagnosis, significantly shorten the delay of treatment time, and is suitable for popularization and application in primary medical institutions.