The invention discloses a magneto-rheological damper with a mixed flow type fluid flowing channel. The magneto-rheological damper is mainly composed of a piston rod, a damper end cover, a sleeve, a piston end cover, a valve bush, a valve element, a floating piston, a magnet exciting coil, a positioning disc, magnetic conductive discs, a lifting lug and the like. A fluid flowing channel among the left magnetic conductive disc, the valve bush and the valve element forms a first section of effective damping gap and a second section of effective damping gap. A fluid flowing channel between the right magnetic conductive disc and the valve element forms a third section of effective damping gap and a fourth section of effective damping gap. When electric conduction is carried out on the magnet exciting coil, the four sections of effective damping gaps generate a magnetic field with a certain size, the viscosity of magneto-rheological fluid flowing through the four sections of effective damping gaps is increased, the yield stress is improved, and therefore pressure difference is formed between a first cavity and a second cavity of the damper. The damping force can be effectively controlled by controlling the magnitude of applied current. The magneto-rheological damper is wide in damping force dynamic adjustment range, simple in structure, small in size and particularly applicable to vibration damping systems of railways, automobiles, bridges and the other structures.