Abstract: Tetraphenyl porphine and tetraphenyl cobaltoporphine were separated by thin layer chromatography.The plate adsorbed with a thin layer of silica gel was used as the stationary phase,and a mixture of petroleum ether and xylol (mixed in the ratio of 2 to 1) was used as the mobile phase (also as developing solvent).The spots of the 2 compounds were separated clearly and without tailing.The proposed method was used as tracing detection in the preparation of TPP-Co.