Abstract: Weizhou12-1N is the oilfield of water injection development with big pressure differential between static and saturation pressure.The injected water source is supplied by Weizhou12-1A platform.And the water pressure of pipe network is 14 MPa,under which the water injection rate is limited,with only 0.25 injection-production ratio.In order to satisfy the injection and mining requirement,pressure boosting and water injection must be done(The net pressure boosting is 7 MPa).However,for the restriction of platform space,increasing equipment on ground is very difficult.The plan increasing the pressure of injected water source to 21 MPa to achieve pressure boosting and water injection by electric submersible pump inverted in the shaft of injecting well.The result of field test shows that,the water injection rate of Weizhou12-1-B15 well increasing from 330 m3/d to 1100 m3/d meets the requirement of injection and mining.The research result fills in the blank of underground pressure boosting and water injection of inversion type submersible electric pump in offshore oilfield in domestic.