Abstract: Objective To investigate the correlation between monocyte to high-density lipoprotein cholesterol ratio（MHR） and left atrial enlargement（LAE） in patients with essential hypertension（EH）. To establish an individualized nomogram prediction model. Methods The clinical data of 889 patients with EH diagnosed in Hebei General Hospital from August 2022 to September 2023 were collected and a retrospective database was established. According to the results of transthoracic echocardiography（TTE）, the patients were divided into LAE group（n=168） and non-LAE group（n=721）. Multivariate logistic regression analysis was used to analyse the risk factors of LAE in EH patients. Based on the obtained risk factors, a nomogram model was constructed, and the receiver operating characteristic（ROC） curveand calibration curve were drawn to verify the model. Results Compared with the non-LAE group, the age, body mass index, systolic blood pressure, pulse pressure, white blood cell count, neutrophil count, monocytes, triglyceride（TG）, low-density lipoprotein cholesterol（LDL-C） and left ventricular end-diastolic diameter（LVEDD） were higher in the LAE group（all P＜0.05）. MHR in LAE group was higher than that in non-LAE group 0.28（0.23, 0.36） vs 0.22（0.17, 0.29）, Z=-7.467, P＜0.001. Multivariate logistic regression analysis showed that gender, age, body mass index, pulse pressure, TG, high-density lipoprotein cholesterol（HDL-C）, LVEDD and MHR were risk factors for LAE in EH patients. The area under the ROC curve（AUC） of the constructed nomogram model was 0.924. The calibration curve showed that the consistency index（C-index） of the model was 0.925, and the slope of the curve was 1, indicating that the model had good performance. Conclusion MHR is correlated with LAE in patients with EH.