A controller for vehicle air conditioner , comprising: a base defining a mounting cavity ; a knob assembly rotatably mounted to the base , wherein at least a portion of the knob assembly is located in the mounting cavity ; and at least one bearing element arranged between the base and the knob assembly , wherein the controller for vehicle air conditioner further comprises: a spring element arranged between the base and the knob assembly , wherein the knob assembly comprises a shift portion which comprises a shift ring , the shift ring forms a plurality of convex portions and a plurality of concave portions which are alternately arranged, the spring element is connected with the base and extends into the concave portion of the shift ring , characterized in that the spring element comprises one selected from a group consisting of: a leaf spring comprising a fixing portion connected with the base and an engaging portion connected to the fixing portion , and the engaging portion extends to the concave portion of the shift ring ; a spring in combination with a shift pin , wherein the spring is connected to the base, the shift pin is located at a distal end of the spring , and the shift pin is urged to the concave portion of the shift ring by the spring ; and a spring in combination with a ball , wherein the spring is connected to the base , the ball is provided at a distal end of the spring , and the ball is urged to the concave portion of the shift ring by the spring . a base defining a mounting cavity ; a knob assembly rotatably mounted to the base , wherein at least a portion of the knob assembly is located in the mounting cavity ; and at least one bearing element arranged between the base and the knob assembly , wherein the controller for vehicle air conditioner further comprises: a spring element arranged between the base and the knob assembly , wherein the knob assembly comprises a shift portion which comprises a shift ring , the shift ring forms a plurality of convex portions and a plurality of concave portions which are alternately arranged, the spring element is connected with the base and extends into the concave portion of the shift ring , characterized in that the spring element comprises one selected from a group consisting of: a leaf spring comprising a fixing portion connected with the base and an engaging portion connected to the fixing portion , and the engaging portion extends to the concave portion of the shift ring ; a spring in combination with a shift pin , wherein the spring is connected to the base, the shift pin is located at a distal end of the spring , and the shift pin is urged to the concave portion of the shift ring by the spring ; and a spring in combination with a ball , wherein the spring is connected to the base , the ball is provided at a distal end of the spring , and the ball is urged to the concave portion of the shift ring by the spring . a leaf spring comprising a fixing portion connected with the base and an engaging portion connected to the fixing portion , and the engaging portion extends to the concave portion of the shift ring ; a spring in combination with a shift pin , wherein the spring is connected to the base, the shift pin is located at a distal end of the spring , and the shift pin is urged to the concave portion of the shift ring by the spring ; and a spring in combination with a ball , wherein the spring is connected to the base , the ball is provided at a distal end of the spring , and the ball is urged to the concave portion of the shift ring by the spring . <EOS>