Aiming at the traditional hydraulic design which is difficult to meet the performance requirements of the downhole turbine generator, an inverse problem optimization design method with blade load as the design variable and output power as the objective function was proposed. Based on the blade load distribution law of the downhole turbine generator, “three-stage” was used to parameterize it, and based on the blade load distribution form of the initial model, the load at NC was linearly increased or decreased, and each time the change was 0.2 times, and six different blade load distribution schemes were designed, and the inverse problem method was used to design the impeller model, and the output power of six schemes was numerically calculated, and the output power of six schemes was calculated. The output power of the six schemes was numerically calculated, the highest output power was got for the scheme Ⅱ with value of 118.867W, the initial model output power was 93.2796W, the lowest output power was got for the scheme Ⅳ with value of 80.77W. The front loading point at the load of scheme Ⅱ was increased by 0.2 times compared with the initial model; the blade load of the blade at the load was linearly increased or decreased each time change for 0.2 times; the blade load distribution scheme designed six different blade load distribution, using the inverse problem approach to design the impeller model, the inverse problem approach to design the impeller model. The blade load was analyzed, and the relationship between the output power of the downhole turbine generator and the load at the front loading point was obtained. Based on the relationship between blade load and performance and the blade optimization algorithm designed, the target blade load distribution scheme applicable to the high performance of downhole turbine generator was obtained after continuous calculation and iteration, and the load at the front loading point of the target blade load was increased by 0.28 times compared with the initial model; based on the scheme for the design of the inverse problem, the comparison of the target blade load and the simulated load was closer; after numerical calculations, the target blade output power was increased and then decreased with the load at the front loading point, which was closer to the simulated load. After numerical calculation, the output power of the counter-problem design model with blade load distribution was 129.8W under the same conditions, which was 10.933W higher than the highest output power in the previous six schemes, with an increase of 9.26%; analyzing the pressure cloud diagram, it can be clearly observed that the location of the highest value of the blade pressure was in the vicinity of the front loading point, which was in the highpressure area, proving that the design of downhole turbocharger based on the blade load distribution had the highest value of the blade pressure, which was in the vicinity of the front loading point. The load distribution on the downhole turbine generator was proved based on the feasibility of the inverse problem optimization design method and theory.