PEG which has excellent resolution for the polar compounds and alkylbenzene, is widely used in capillary gas chromatography as the polar stationary lipid.In the past, people explored rarely on PEG-20M fused silica capillary column preparation methods, just directly coated in most cases.The method cant change the non-wetting feature of the fused silica.Moreover, determination dead time(Tm) is often based on the retention time of methane.The dosage of methane is very little, coupled with volatile methane difficult to preserve.So its necessary to improve the method.This paper starts with the improvement the coating method of elastic quartz capillary column, explore the substituted approach to determine Tm with butane, evaluate the prepared different kinds of columns (different diameter and different film thickness), to examine the modified coating methods and usage scope of different columns.This study is of great significant for taking full adventure of flexible PEG-20M capillary column separation capacity and selecting capillary columns in daily analysis.