Abstract: From 1972 to 1989 years，the mortality of malignant Tumor is 267. 14/100,000 in coking employees in Taiyuan Iron and Steel Company,which is much higher than those of controls(other employees 32.29/100,000 and normol population 76.50/100,000). In order to study the etioiogy of malignant tumor. the hair were determined frpm the 57 employees in the coking plant and 37 cotrols in the steel institute，The levels of Zn Ca in coking plant employees were 135.33,1671,58 ppm, and they were significantly lower than that of controls 149, 53 2483,94 ppm (P<0.0l and P<0.05). The levels of Cu，Cu/Zn, Mn in coking plant employees were 10, 40,0.077 and 0.76 ppm, which were significantly higher than that of controls 9,19,0.063 and 0.46ppm (P<0.05,P<0.0l and P<0.0l)，The result suggested that the decreased of Zn，Ca，and the increased Cu,Cu/Zn, Mn in the hair of coking employees may be one of the reasons why the incidence of malignant tumor in coking employees.