Abstract: Enhancing oil recovcry with D.C. electric field is' anew method to which much importance havc been attached since 1990s. Several field trials are very successful. It can effeetively enhance oil recovery through electric heating, electric osmose, electric motivation and electrophoresis in D. C. electric field, i. e. through joint action of electrodynamics, electro - heat and electrochemistry.This paper introduces its field application, establishes aphysical model and discusses its mechanism.