A computer program of on-line multi-component analysis for an organic elemental analyzer was described. Under the control of the proposed program, an elemental analyzer can perform both normal elemental analysis (EA) and multi-component analysis automatically. Eight mixtures of standard samples and nine synthetic copolymers were performed to check the reliability of program. The analytical results of styrene- N, N′-diisopropylacrylamide copolymer samples were compared with the determined results obtained from ultraviolet visible derivative spectroscopic (DS) method. The results show that the deviations for the mixtures of standard samples are <2% for two and three components samples. In the case of synthetic copolymers, the average deviation between the two methods is 1.96%. It indicates that the proposed program is applicable for the combustion-GC type organic elemental analyzer.