The invention provides an electric automobile air conditioning system which comprises a compressor, a four-way valve, an extra-automobile heat exchanger, a first intra-automobile heat exchanger, a second intra-automobile heat exchanger, a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a first control valve and a second control valve. When the extra-automobile heat exchanger needs to be used for defrosting, a first end opening of the four-way valve communicates with a fourth end opening, a second end opening communicates with a third end opening, and a second branch communicates with the first pipeline and the second pipeline; and the first control valve controls the third pipeline to be connected, the second control valve controls the fourth pipeline to be connected, and a first branch is disconnected from the first pipeline and the second pipeline. The invention further provides an electric automobile and a control method of the electric automobile air conditioning system. By the adoption of the electric automobile air conditioning system, the electric automobile and the control method of the electric automobile air conditioning system, continuous heating in the automobile can be achieved in the defrosting process of the extra-automobile heat exchanger, and the comfort in the automobile is guaranteed.