The effect of the trace elements on retinopathy of prematurity (ROP) were studied. Thirty preterm infants who had potential high risk factors of ROP were selected as observation group and 18 normal infants as control groups. By using atom spectrophotometer, the contents of serum trace elements (Mg, Cu, Zn, Mn, Se) were measured and analyzed statistically. The contents of serum Zn, Cu and Se in observation group were 0.75+/-0.22, 0.41+/-0.20 and (134.07+/-71.57)x10(-3) mg/L respectively, and 0.55+/-0.12, 0.65+/-0.194 and (202.92+/-44.71)x10(-3) mg/L in control group respectively (P<0.01). The contents of Cu and Se were obviously lower and that of Zn higher in observation group than those in control group. The same results were obtained between the infants with ROP and controls (P<0.01). However, there was no significant difference in the contents of serum Mg and Mn between two groups (P>0.05). It was concluded that the contents of serum Cu and Se in preterm infants who had high risk factors of ROP were obviously lower than in the controls. The contents of serum Cu and Se in the ROP infants were also much lower while contents of Zn much higher. Attention should be paid to the detection of the trace elements in preterm infants in order to prevent the deficiencies of Cu and Se. Only in this way can we prevent the deficiencies of Cu and Se, so as to decrease the ROP risk factors and prevent the disease.