Objective   To investigate the clinical significance of serum monocytes/high-density lipoprotein cholesterol ratio(MHR), (neutrophils+monocytes)/lymphocyte ratio (NMLR), and calcium/magnesium ratio (Ca/Mg) among  patients with primary hypertension (PH) in Xining area of Qinghai Province. Methods  A total of 528 subjects were enrolled, and they were divided into healthy control group (n=179) and PH group (n=349) according to  blood pressure measurement results. According to the 2018 Chinese Guidelines for the management of hypertension,  patients in the PH group were further divided into grade 1 PH group (n=116), grade 2 PH group (n=111) and grade 3 PH group (n=122). By using multivariate Logistic regression analysis, the independent risk factors of the disease were clarified in the PH group. Routine blood testing  and biochemical detection were performed to measure the levels of MHR, NMLR and Ca/Mg. Spearman correlation analysis was employed to explore the correlation between MHR, NMLR, Ca/Mg levels and the classification of hypertension. Results  Multivariate Logistic regression analysis showed that Ca/Mg and NMLR were independent risk factors for PH. Ca/Mg and NMLR in the PH group were significantly higher than those in the control group (P<0.05). Compared with the grade 1 PH group, Ca/Mg and NMLR levels in the grade 3 PH group increased significantly (P<0.05). Ca/Mg, NMLR and MHR levels were positively correlated with the classification of hypertension (P<0.05). Conclusion  NMLR, Ca/Mg and MHR levels are closely associated with the severity of PH. Monitoring NMLR and Ca/Mg is helpful for making early identification of high-risk PH patients and   correspondingly providing clinical intervention.