To accomplish the high-precision testing of aspherical mirror with large aperture and deviation, a hybrid compensation detection model combining subaperture stitching with compensator is proposed. The model can realize high resolution detection of the detected mirror and provide guidance for subsequent processing when the accuracy of the mirror is not high enough to be achieved by the dynamic range of the interferometer. At the same time, it′s beyond the testing accuracy of the profile measurement. To evaluate the validity of the proposed model, a 1450 mm off-axis parabolic mirror with the hybrid compensation method is tested. To evaluate the testing accuracy, the testing result with the subaperture testing result is compared. The peak and valley value and root mean square value of the residual between them is 0.030λ and 0.003λ respectively, verifying the accuracy and validity of the model.