Molecular imprinting of theophylline in poly (methacrylic acid| ethylene dimethacrylate) as CEC stationary phases was synthesized by an in situ photo|initiated polymerization reaction. The effect of electrolyte pH on xanthine derivatives and the stability of MIP column performance were investigated. the relative standard deviation ( D RS ) of migration time of five consecutive runs on MIP column was in the range of 2.2%|3.1%.The reproducibility of migration time column to column of M(A) was in the range of 3.8%|4.9%. The highest column efficiency was more than 140 000 plates per meter. The MIP capillaries had showed better selective for theophylline, which comparing with the reference column. The urine sample was separated by spiked 5×10 -4 mol5L -1 theophylline. Molecular imprinting of theophylline in poly (methacrylic acid | ethylene dimethacrylate) as CEC stationary phase was synthesized by an in situ photo. initiates polymerization reaction. The effect of electrolyte on xanthine derivatives and the stability of MIP column performance were investigated The relative standard deviation (D RS) of migration time of five consecutive runs on MIP column was in the range of 2.2% | 3.1%. The reproducibility of migration time column to column of M (A) was in the range of The highest column efficiency was more than 140 000 plates per meter. The MIP capillaries had showed better selective for theophylline, which compares with the reference column. The urine sample was separated by spiked 5 × 10 -4 mol 5L -1 theophylline.