The invention discloses a mixed-type sludge solar dryer which mainly consists of seven parts such as solar air collector, an air valve, a fan, a conveying belt, an air pipe, a drying chamber, a gas stove and the like. The mixed-type sludge solar dryer utilizes solar energy as a main heat source and methane generated in a sewage treatment process as an auxiliary heat source, so that continuous drying in different time and different seasons can be realized, not only can energy conservation and environmental friendliness be realized, but also the operating cost is relatively lower than those of other drying devices.