Abstract: A Comparative study is made on the separation performance of chromatographic stationary phase of several high polymers. A good mixed stationary phase is chosen for the determination of trace dimethyl ether, methanol, methyl-tert-butyl ether(MTBE), tert-butanol and other oxygen compounds in unreacted C₄ in the MTBE Unit by GC. Calculation is made by internal standard method. Detection limit is up to 10×10^-6(W/W), and no interference of other compounds take place in the determination.