The invention provides a process which can reduce the impurity of 1,1,2,2-tetrafluoroethane and 2-chloro- 1,1,1,2-tetrafluoroethane from HFA 134a without the need of tedious distillation. The process comprises of contacting impure 1,1,1,2-tetrafluoroethane with polyethylene glycol to remove the impurities of 1,1,2,2-tetrafluoroethane and 2-chloro-1,1,1,2-tetrafluoroethane. The process is simple and economic.