Abstract: Because CFCs deplete the ozone layer and HFCs have high global warming potentials, many countries have been reinvestigating low GWP refrigerants as alternatives in household air conditioners, one of which is R290 as the alternative for R22. But the most important problem is how to choose the suitable lubricant for refrigerant R290. In this paper, the design method of lubricant was proposed through analyzing the lubrication in rotate compressor of household air conditioners and studying on properties of several oils in R290 refrigerant.