The invention relates to a detection system for detecting the liftoff of an engineering vehicle and tyres of the engineering vehicle, and a detection method of the detection system. The detection system comprises at lease one detection assembly and a signal processing unit, the detection assembly comprises a position sensor and a detection body, the position sensor is installed on one of a frame and an axle, the detection body is installed on the other one of the frame and the axle, when the tyres of the engineering vehicle are lifted off , the relative position of the position sensor and the detection body is changed, so that the state of the position sensor changes, and the signal processing unit is connected with the position sensor so as to output the corresponding prompt message and/or control signal according to the state of the position sensor. The engineering vehicle comprises the detection system for detecting the liftoff of the tyres. The detection method comprises the step of sampling the state of the position sensor, and outputting a signal characterizing the liftoff of the tyres when the state of the position sensor is converted from the first state value to the second state value. With the detection system, the liftoff of the tyres can be guaranteed after the vehicle is leveled.