Objectives: Magnesium is associated with vascular calcification and cardiovascular disease in hemodialysis patients. The aim of this study was to investigate the magnesium level and blood pressure in hemodialysis patients. Methods: A cross-sectional study was conducted in 114 maintenance hemodialysis patients with complete follow- up data from June 2020 to May 2021 in Beijing Tsinghua Changgung Hospital, Tsinghua University. Baseline data including gender, age, primary disease, biochemical parameters and pre- to post-hemodialysis blood pressure were recorded. Grouped with serum magnesium level and the correlation between magnesium and blood pressure were analyzed. Results: 114 patients with hemodialysis were enrolled in the study . The primary disease was diabetic nephropathy (52.6%). Mean serum magnesium concentration was (1.11 ± 0.13) mmol/L, 36% patients with normal serum magnesium concentration (0.7-1.05mmol/L ), 64% with hypermagnesemia (>1.05mmol/L) and no patients with hypomagnesemia (<0.7mmol/L ). The results showed the systolic blood pressure, the diastolic blood pressure of pre-dialysis and parathyroid hormone level were lower in hypermagnesemia group. Hemoglobin, total protein, albumin, serum calcium and serum potassium level were higher in hypermagnesemia group. Correlation factor analysis showed that serum magnesium was positively correlated with hemoglobin, total protein, albumin, serum calcium and serum potassium (P < 0.05). Conclusions: Magnesium were associated with nutrition, calcium phosphorus metabolism, anemia and blood pressure. These factors we should pay more attention in clinical practice.