The invention relates to a high-low cycle complex fatigue test clamp for a mortise-joint structure of a small blade of a turbine on an aeroengine. By adoption of the high-low cycle complex fatigue test clamp, synchronous loading of longitudinal low-cycle large load, horizontal high-cycle vibration load and heat load in test of the mortise-joint structure of the small blade of the turbine is realized. The high-low cycle complex fatigue test clamp is characterized in that a top holding structure is clamped on a fatigue machine, and a turbine disc is fixed by a clamping bolt; the turbine disc isconnected with the turbine blade in a mortise-joint manner; a small blade clamp clamps a blade body of the turbine blade by means of frictional force; the bottom part of the small blade clamp is tightly screwed with a high-cycle excitation rod by a bolt, and the top part of the small blade clamp is in clearance fit with a force-transmission top plate by a shaft-hole structure; the force-transmission top plate is in clearance fit with force-transmission pulling plates by shaft-hole structures, the stability of the structure is maintained by fixed long bolts; the force-transmission pulling plates are tightly screwed with a low-cycle force applying structure by nuts; the lower part of the low-cycle force applying structure is clamped by the fatigue machine; the fatigue machine applies the low-cycle load, the excitation rod is externally connected with an exciter to apply the high-cycle load, and the mortise-joint position is externally connected with an induction heating copper coil to apply the heat load. The high-low cycle complex fatigue test clamp has the beneficial effects that stable clamping of the mortise-joint structure of the small blade of the turbine can be met, and the high-low cycle compounding fatigue under the high-temperature condition can be realized.