The invention discloses a medium-high temperature phase change heat storage solar hot air heater, which comprises a heat preservation box body, a heat storage body and a groove type solar heat collector. The heat preservation box body includes: an air mixing box located on the upper portion of the heat preservation, a normal-temperature air supply unit and an air outlet which are formed in the twosides of the air mixing box respectively and communicated with the air mixing box, a cavity which is formed below the air mixing box and communicated with the air mixing box, and a hot air supply unit which is located below the cavity and communicated with the cavity and the exterior of the heat preservation box body. By means of the device, cold and hot air flowing out of double air ducts of thehot air duct and the normal-temperature air duct can be uniformly mixed in the air mixing box, and the controller adjusts the rotating speeds of the two fans according to the temperature sensors, sothat the air volume of the cold and hot air is adjusted, and the purpose of stabilizing the outlet temperature is achieved. The air outlet temperature is adjusted by adjusting the rotating speeds of the two fans, so that the air outlet temperature reaches a set value; due to the high heat collection efficiency of the trough type solar heat collector, the phase change material obtains high-grade heat energy, so that the heating requirement at night is met, the structure is simple, the operation time is long, and use is convenient.