Objective - To analyze the relationship between cobalt level of post shift urine and individual exposure level of ， cobalt and its compounds in cobalt exposed workers and to explore the feasibility of using urine cobalt as a biomarker. Methods - A total of 148 occupational cobalt exposed workers from a new material company were selected as the exposed ， - - group and 44 non occupational cobalt exposed workers from the company were selected as the control group using the typical sampling method. The exposure concentration of time weighted average of cobalt and its compounds in the workplace air of the - two groups was determined by inductively coupled plasma mass spectrometry as the individual exposure level. The cobalt levels - - of pre shift and post shift urinary samples of the two groups were detected by this method. The linear relationship between the - cobalt level of post shift urine and the individual exposure level of cobalt and its compounds in the air of the workplace was Results - 3 analyzed. The individual exposure level of cobalt and its compounds in the exposed group was 1.10 131.71 μg/m with （M） 3 the median of 12.23 μg/m. No cobalt and its compounds were detected in the workplace air in the control group. The cobalt - - levels of pre shift and post shift urines in exposed group were higher than those in the control group at the same time point （M： vs ， vs ， P ） - - 1.54 0.56 μg/L 8.77 0.83 μg/L all <0.01 . The cobalt level of post shift urine was higher than that in pre shift （M： vs ，P ）， urine in the exposed group 8.77 1.54 μg/L <0.01 and it was positively correlated with the individual exposure level （ ，P ） ， of cobalt and its compounds Spearman correlation coefficient=0.86 <0.01 . After common logarithm conversion the linear regression equation of the cobalt level of post shift urine and the common logarithm of individual exposure level of cobalt and （x） ：ŷ x（ ；F ， its compounds in the exposed group was as follows = −0.178 + 0.988 coefficient of determination=0.72 =374.75 P ；t ， P ） Conclusion - <0.01 = - 19.36 <0.01 . There was a linear correlation between cobalt level of post shift urine and occupational cobalt exposure level of cobalt exposed workers. Urinary cobalt can be used as a biomarker of occupational cobalt