One-key control method and system for crane extending and retracting and crane

The invention discloses a one-key control method and system for crane extending and retracting and a crane. The method includes the steps that a control signal sent by a crane extending and retracting key is received; whether the crane extending operation is performed or not is judged according to state information of chassis supporting legs and information of an upper crane part of the crane; if yes, the crane is controlled to extend to be in a lifting operation state; and if not, the crane is controlled to retract to be in a totally retracted traveling state. By means of the one-key control method and system for crane extending and retracting and the crane, potential safety hazards of false operation caused by false touch can be avoided, an emergency exit control mode is added, the action stop response time of a crane body can be shortened, and false operation is avoided in the process of performing all the actions. Meanwhile, the operation process of the crane is simplified, and the intelligence level of c