Objective: To analyze the levels and distribution characteristics of blood cadmium and urinary cadmium in American adults, to analyze the relationship between blood cadmium and urinary cadmium and pulmonary function dose response, and to explore the effect of this index on the risk of chronic obstructive pulmonary disease. Methods: In March 2022, 3785 patients from 2007 to 2012 in NHANES database were selected as the subjects. Collect demography data such as gender and age, and test data such as lung function, blood cadmium concentration and Urine cadimium concentration. The relationship between blood and urine cadmium levels and lung function and pulmonary function and chronic obstructive pulmonary diease (COPD) was analyzed by Mann-Whitney U test or Kruskal-Wallis H test, multivariate linear regression and restricted cubic spline method. Results: The geometric mean of blood cadmium and urine cadmium in American adults was 0.37 g/L and 0.28 g/L, FEV(1) and FEV(1)/FVC among different cadmium exposure groups was statistically significant, and there was a negative linear dose-response relationship between serum Cd and urine Cd concentrations and FEV(1)/FVC levels (P(overall)<0.001, P(non-linear)=0.152; P(overall)<0.001, P(non-linear)=0.926). Compared with the lowest quartile concentration (Q1), the highest quartile blood cadmium concentration (Q4) (OR=1.934, P(trend)=0.000) and urinary cadmium concentration (OR=1.683, P(trend)=0.000) may increased the risk of chronic obstructive pulmonary disease. Conclusion: There is a negative correlation between blood cadmium, urinary cadmium levels and lung function in American adults, and cadmium may increase the risk of chronic obstructive pulmonary disease.