Abstract: For the central rib butted horizontal tail structure, the asymmetric bending moment loads were measured by the direct measurement method and the proposed phenomenological fitting method. By carrying out virtual test and ground load calibration test successively, the asymmetric load models of the two measurement methods were established respectively, and their applicability and accuracy were studied. The ground load calibration test and flight test results show that the phenomenological fitting method could effectively complete the asymmetric load measurement of the horizontal tail structure, and the maximum value of the ground load calibration test model inspection error was 1.57%. In the direct measurement method, due to the connection of butt ribs and flat tail joints which near the central symmetry plane, the local force transmission of strain gage station was relatively complex. The accuracy of direct measurement method was poor, and the ground load calibration test model inspection error was up to 8.11%.