A multistate resistance adjusting device for a non-pull cord window blind includes a base, an adjusting unit, and an elastic member. The base has a bottom trough provided on the periphery thereof with positioning grooves. The adjusting unit has a control pin provided with a transmission portion rotatable and vertically movable on the base and a positioning portion provided on the outer peripheral surface of the transmission portion and connected with an adjusting rod. When the positioning portion is engaged with one of the positioning grooves, the control pin is disabled from rotating relative to the base and adjusting the resistance applied on the lift transmission cord. When the control pin is moved upwardly to separate the positioning portion thereof from the positioning groove, the control pin is rotatable relative to the base, and the resistance applied on the lift transmission cord is adjustable through the adjusting rod.