The invention discloses an engine rocker type variable valve device. A cam, a motor, a gear rack transmission, a rocker and a connecting rod are included. The engine rocker type variable valve deviceis fixed to an air cylinder cover. When the rotation speed of an engine changes, the motor is used for driving a gear 6 to rotate with the corresponding angle, a rack 4, a rack shaft 2, the connectingrod 7 and a sliding block 13 are driven to do the same-ration horizontal movement motion, and accordingly the rocker ratio of the rocker 12 is changed; through pushing of the cam 15, the lift of a valve 19 is continuous and changeable, and the problem that under different work conditions, the valve lift of the engine cannot be continuous or changeable is solved; and the engine conducts sufficientair inflow and outflow under different work conditions, the combustion environment in a cylinder is changed, and accordingly, fuel economy and emission performance of the engine are improved.