The hot air circulation oven of Changzhou Ouna drying equipment Co., Ltd. has increased the heat transfer effect, and the moisture of the material in the box is gradually reduced. The oven equipped with low noise and high temperature proof axial flow fan and automatic temperature control system, the circulatory system fully closed, the thermal efficiency of the oven is from the traditional drying room 3 - 7% increase to the current 35 - 40%, the highest thermal efficiency up to 70%. The whole machine has low noise, running balance, temperature control, convenient installation and maintenance.