A control method for an air-conditioning system, wherein the air-conditioning system comprises a compressor, a cooling device, a heating device, an electronic expansion valve, and a control assembly, the control assembly is electrically connected to the compressor, the control assembly is electrically connected to the electronic expansion valve, and the control assembly of the air-conditioning system adjusts an opening of the electronic expansion valve, the control method comprises: acquiring refrigerant pressure data and air temperature data at a predetermined position in the air conditioning system from predetermined positions of the air-conditioning system, and the control assembly receiving electric signals of the refrigerant pressure data and the air temperature data acquired, or electric signals, converted from the refrigerant pressure data and the air temperature data acquired; acquiring, by the control assembly, a fine adjustment pressure range and an alert pressure range of the electronic expansion valve according to the electric signal related to the air temperature data received by the control assembly, an upper limit of the fine adjustment pressure range is lower or equal to a lower limit of the alert pressure range; determining, by the control assembly, whether the current refrigerant pressure data is within the fine adjustment pressure range, adjusting an opening of the electronic expansion valve according to a first adjustment method preset by the control assembly, if the determination result is that the current refrigerant pressure is within the fine adjustment pressure range; determining, by the control assembly, whether the current refrigerant pressure data is within the alert pressure range, adjusting the opening of the electronic expansion valve according to a second adjustment method preset by the control assembly, if the determination result is that the current refrigerant pressure is within the alert pressure range; wherein a speed for adjusting the opening of the electronic expansion valve according to the second adjustment method is greater than a speed for adjusting the opening of the electronic expansion valve according to the first adjustment method; controlling the electronic expansion valve to relief pressure, if the determination result is that the current refrigerant pressure exceeds an upper limit of the alert pressure range. acquiring refrigerant pressure data and air temperature data at a predetermined position in the air conditioning system from predetermined positions of the air-conditioning system, and the control assembly receiving electric signals of the refrigerant pressure data and the air temperature data acquired, or electric signals, converted from the refrigerant pressure data and the air temperature data acquired; acquiring, by the control assembly, a fine adjustment pressure range and an alert pressure range of the electronic expansion valve according to the electric signal related to the air temperature data received by the control assembly, an upper limit of the fine adjustment pressure range is lower or equal to a lower limit of the alert pressure range; determining, by the control assembly, whether the current refrigerant pressure data is within the fine adjustment pressure range, adjusting an opening of the electronic expansion valve according to a first adjustment method preset by the control assembly, if the determination result is that the current refrigerant pressure is within the fine adjustment pressure range; determining, by the control assembly, whether the current refrigerant pressure data is within the alert pressure range, adjusting the opening of the electronic expansion valve according to a second adjustment method preset by the control assembly, if the determination result is that the current refrigerant pressure is within the alert pressure range; wherein a speed for adjusting the opening of the electronic expansion valve according to the second adjustment method is greater than a speed for adjusting the opening of the electronic expansion valve according to the first adjustment method; controlling the electronic expansion valve to relief pressure, if the determination result is that the current refrigerant pressure exceeds an upper limit of the alert pressure range.