The invention relates to a toner cartridge with a locking mechanism, including a body provided with a top cover and used for receiving a developer, wherein the locking and unlocking mechanism used for locking the toner cartridge into an image forming apparatus is arranged on the body. The locking mechanism includes a handle hinged with the top cover, a gear fixedly connected with the handle, a locking lever capable of reciprocating and a torsion spring used for realizing the automatic reset of the handle. A rack engaged with the gear is arranged on the locking lever. Moreover, the handle is driven to be close to the top cover under the action of a torque force of the torsion spring under the locking state, and the gear is engaged with the rack to drive the locking lever to be extended out of the top cover so as to lock the toner cartridge. When the handle is under the unlocking state by overcoming the torque force of the torsion spring under the action of an external force, the gear and the rack are operated to drive the locking lever to be retracted into the top cover so as to unlock the toner cartridge. Unlocking and locking can be realized through a tensile force of a human hand and the reset of the torsion spring.