Abstract: Contents of C, Si, Mn, P and S in steel samples of small sized wire rods with diameter more than 4 mm, were determined by opto-electro-direct-reading spectrometry. Influential factors, including methods of sampling, and sample preparation and choice of standard sample were discussed. Under the optimized experimental conditions, values of RSD′s (n=10) of the 5 elements were found in the range of 0.76%-2.7%. The proposed method was applied to the analysis of 3 batches of samples, and the results obtained were in conformity with those given by 3 other labs.