Abstract: A special injector is presented in this paper, inwhich the steam may be freely injected into the oil pipeline. Heavy oil is heatedby the steam released latent heat. With the increase of temperature, the oil viscosityand pressure drop can be reduced greatly. The injector is capable ofimmediate heating and transporting oil without blockage.This technical feasibility has been tested in the pipeline at Liaohe oilfield and good results were obtained.