The utility model provides a power umbrella device for testing a horizontal water injection well. The power umbrella device comprises a testing sleeve, a cable channel, an elastic deformation piece and a driving assembly, the elastic deformation piece sleeves the upper end of the test sleeve, the cable channel sequentially penetrates through the elastic deformation piece and the test sleeve and extends out of the test sleeve, and the lower end of the test sleeve is used for being connected with a test instrument; the driving assembly is located in the test sleeve, is connected with the elasticdeformation part and is used for driving the elastic deformation part to move in the axial direction of the test sleeve, so that the elastic deformation part expands under the extrusion of the driving assembly, and the cross section area of the elastic deformation part is increased. According to the power umbrella device for testing the horizontal water injection well, the elastic deformation piece expands under extrusion of the driving assembly, the cross section area of the elastic deformation piece and the gravity of normal water injection in the oil pipe are increased, and the testing sleeve and the testing instrument are driven to continue to move forwards when the well deviation angle of the well deviation section of the horizontal water injection well is large.