Control method and device of multi-connected air conditioning unit and multi-connected air conditioning unit

The invention discloses a control method and a device of a multi-connected air conditioning unit and the multi-connected air conditioning unit. The method comprises the following steps: an operation state of the multi-connected air conditioning unit is divided into at least two substates; each substate generates unique state conversion event at any operation time of the multi-connected air conditioning unit; and the conversion of the operation state is controlled according to the state conversion event. The method can overcome such defects as weak control effectiveness, weak flexibility and high operation load in the prior art, and realizes the beneficial effects of good control effectiveness, good flexibility and low operation load.