The invention discloses a gear rack clearance eliminating mechanism. The gear rack clearance eliminating mechanism comprises a bevel wheel power component, a reducer mounting plate component and a bevel wheel adjusting component, wherein the bevel wheel power component and the bevel wheel adjusting component are respectively and fixedly mounted on the reducer mounting plate component; the bevel wheel power component comprises a motor, a reducer, a bevel wheel mounting plate, a bevel wheel and racks meshed with the bevel wheel, which are sequentially connected together; the reducer mounting plate component comprises a reducer mounting plate, a bevel wheel dust cover and a reducer mounting plate sheet; the bevel wheel adjusting component comprises a bevel wheel adjusting rod, a belleville spring group and a bevel wheel adjusting rod mounting seat; the bevel wheel adjusting rod is mounted in the bevel wheel adjusting rod mounting seat; the belleville spring group is arranged between the bevel wheel adjusting rod and the bevel wheel adjusting rod mounting seat. The gear rack clearance eliminating mechanism disclosed by the invention is simple in structure, stable and reliable; in the meantime, the gear rack center distance adjusting mechanism which is easy to adjust can be used to eliminate the clearance in the gear rack transmission process, in order to ensure the transmission accuracy.