Abstract: Abstrsct  Objective  To investigate the correlation between serum levels of 1,25dihydroxyvitaminD3(1,25(OH)2D3)、calcium(Ca2+) and FEV1 of patients with chronic obstructive pulmonary disease(COPD) patients. To explore the relationship between the above-mentioned mass and the Severity of COPD. Methods  Subjects were 30 patients with COPD to be parted as acute stage group and stable stage group. We measured the concentration of 1,25(OH)2D3 、serum Ca2+、serum phosphorus(P) in the serum of two stages. We obtained the data of blood gas analysis and pulmonary function tests. Results  The concentration of serum 1,25(OH)2D3、Ca2+ and P were significantly lower in acute stage group than in the stable stage group. The concentration of serum 1,25(OH)2D3 and Ca2+ positively correlated to FEV1（％）.Conclusion  The concentration of serum 1,25(OH)2D3 and Ca2+ were concerned with FEV1（％）,it suggests that above-mentioned mass may potentially prevent the future deterioration of pulmonary function and reduce case fatality rate.

Key words: chronic disease, Calcitriol, calcium, phosphate