The invention discloses a humidifier and a control method and circuit thereof. The control circuit of the humidifier comprises an encoder and a controller, wherein the encoder is provided with a rotary shaft and a first switch and is used for outputting data signals corresponding to the rotation direction of the rotary shaft and a switching state of the first switch, the controller is connected with the signal output end of the encoder and used for controlling the humidifier according to the data signals. By means of the humidifier and the control method and circuit thereof, the problem that the control circuit of a humidifier in the prior art is complicated is solved, and further the effect of reducing the complex of the control circuit and cost input is achieved.