The invention discloses an electric horizontal swing-vibration type grain grading device aiming at enhancing the grading effect, improving the grading efficiency and relieving the labor intensity of workers. The device comprises a motor base, a variable-frequency motor, a crank, a combined connecting rod, a grain bin, a base, two insertion plates and an impact pad. The crank, the combined connecting rod and the grain bin form a crank and rocker mechanism which is driven by the variable-frequency motor to swing circumferentially in a reciprocating manner. The motor base is fixed to a foundation. The variable-frequency motor is fixed to the motor base through a bolt. The extending end of the variable-frequency motor is connected with one end of the crank through a general flat key. A round hole in the other end of the crank and a round hole in the left end of the combined connecting rod form a hinge through a loose bolt. The device has the two functions of segregation layering and screening and can be used for separation for removing impurities from grain as well as separation and grading of Chinese herb or grass seeds and impurities.