The utility model proposes a coning friction driving reducer, comprising a reducer shell body and a planetary wheel system, wherein a central wheel is fixedly connected on an import shaft, the planetary wheel bear seat is hinge connected with planetary rack, the planetary rack is fixedly connected on an export shaft, the planetary wheel, the central wheel and a fixing wheel are all coning wheels, the angle theta between the planetary wheel axial line and the central wheel axial line is above 0, each planetary wheel bear seat and the end hinge connected with planetary rack are equipped with springy devices. Since the reducer adopts the coning friction driving planetary wheel system structure, only a tiny axial pushing force along the planetary wheel axial direction can generates lengthwise positive pressure times of the axial pushing force, and the lengthwise pressure can provide the pressure needed by the friction driving. Compared with the prior reducer the utility model has the advantages of simple structure, light weight, small volume, high driving efficiency, long using life, being able to overloading protection, lubrication without lubricate oil, high reducing ratio, stable rotation, simple manufacturing craft and low using and maintenance cost.