When the flat drive belt drives, the belt is sleeved on the smooth wheel surface and is driven by the friction between the belt and the wheel surface. The transmission types include open drive, cross drive and semi-cross drive, which are respectively suitable for different relative positions and different rotation directions of the driving shaft and the driven shaft. The flat belt drive has simple structure, but is easy to slip, and is usually used for transmission with a transmission ratio of about 3.

According to different uses, transmission belts can be divided into general industrial transmission belts, automobile transmission belts, agricultural machinery transmission belts and household appliances transmission belts. Friction type drive belt can be divided into flat belt, V-belt and special belt (multi-wedge belt, round belt) according to its different section shape.