The work aims to prepare a low density polyethylene permselective membrane applied with diethanolamine/polyvinyl alcohol (PVA) and study its properties. With diatomaceous earth as additive, low density polyethylene (LDPE) as basal membrane, and composite polyvinyl alcohol (taking diethanolamine as the amine carrier) as coating, a new permselective membrane was prepared with membrane solution applied on the LDPE memberane. The influences of the gas permselective performance of the permselective membrane of diethanolamine carrier and the diethanolamine carrier on the structure and performance of permeable membrane were studied. The maximum permeability coefficient ratio of CO2 and O2 of the permselective membrane prepared with diethanolamine/PVA in the test can reach up to 5.13. The membrane prepared has improved the penetration rate of CO2 and the selectivity coefficients of CO2 and O2. With the increase of diethanolamine carrier content, the tensile strength of composite membrane does not change significantly, but the elongation at break first increases slightly with the increase of amine carrier content.