The invention discloses an automatic grass root harvesting and pulverizing and organic fertilizer preparing machine which comprises a machine box. The machine box is a box body with an opening in theupper side. The whole box body inclines rightwards by a certain angle. A driver is installed on the lower side of the box body. Crawlers are installed on the two sides of the box body. A pulverizer isinstalled on the upper left side of the opening. A harvesting device is installed on the left side of the box body. A vibrator is installed on the lower bottom side of the rear side of the box body.The harvesting device comprises a bucket, a motor, lower shears, upper shears and a hydraulic cylinder. The bucket is connected with the machine box through a rotating shaft. The hydraulic cylinder drives the bucket to rotate. The upper shears are installed on the left side of the bucket, the lower shears are installed on the lower side of the upper shears, a collecting device is installed on theupper side of the bucket, the lower shears are installed on the upper shears through an inverted trapezoid shape, and the motor drives the lower shears to move in the forward and backward directions back and forth. The collecting device is connected with the pulverizer. The driver provides power for the crawlers, the motor, the hydraulic cylinder, the pulverizer and the vibrator.