A turbine blade structure for improving aerodynamic efficiency of low-pressure turbine blades, including: a suction side, a pressure side, multiple dimples and a blade body. The suction side is an outer convex side of the blade body. The pressure side is an inner concave side of the blade body. The dimples are arranged on the suction side in pairs. Each dimple forms an inclination angle β with an air flow. The air flow includes a first fluid and a second fluid, and the energy of the first fluid is lower than that of the second fluid. Each dimple sucks the first fluid at a first end when the air flow passes a surface of the blade body, and allows the first fluid to spirally flow along an inclined direction in each dimple to form a spiral vortex, and discharge the first fluid through a second end.