The invention relates to a hydraulic conveying system for solid particles. The hydraulic conveying system comprises a material conveying pipe, a water replenishing pipe, a main water pump and a solid particle adding hopper, wherein the length direction of the material conveying pipe is taken as the front and back direction, and the rear end of the material conveying pipe is connected with the water outlet of the main water pump; the lower end of the solid particle adding hopper is connected with the left upper part or the right upper part of the material conveying pipe through a connecting pipe; one end of the water replenishing pipe is connected with the material conveying pipe between the solid particle adding hopper and the main water pump, and the other end of the water replenishing pipe is connected with the upper part of the solid particle adding hopper; and a regulating valve is arranged on the water replenishing pipe. The hydraulic conveying system has the advantages of reasonable design, easiness in operation, high degree of automation, strong controllability, high conveying efficiency and difficulty in blocking, avoids the abrasion effect of the solid particles on the main water pump and an enhancement type water pump, has strong practicality, and is easy to be popularized and applied.