The invention discloses an extension-type solar medium-high temperature air heating device, which belongs to the technical field of solar heating and comprises a plurality of thermal-collecting tubes and corresponding thermal-concentrating devices, wherein the plurality of thermal-collecting tubes are serially communicated with each other; the thermal-concentrating devices are fixedly arranged onthe periphery of each thermal-collecting tube. The device has a simple structure, can heat the air gradually, has high thermal efficiency, can provide medium-high temperature air, and is used for industry and agriculture.