Multi-temperature air conditioning system, control method thereof and transport refrigeration vehicle

A multi-temperature air conditioning system, comprising:

• an outdoor unit, in which a compressor, a first stop valve, an outdoor heat exchanger, and a second stop valve connected through pipelines are arranged, wherein, the first stop valve is arranged between a first end of the outdoor heat exchanger and an exhaust port of the compressor, and the second stop valve is arranged between a second end of the outdoor heat exchanger and a suction port of the compressor, and wherein the first end of the outdoor heat exchanger is opposite to the second end of the outdoor heat exchanger;
• a first type indoor unit, in which a first indoor heat exchanger, a first throttling element, a third stop valve, and a fourth stop valve are respectively arranged, wherein, a first end of the first indoor heat exchanger is connected to the second end of the outdoor heat exchanger through the first throttling element, a second end of the first indoor heat exchanger is connected to the exhaust port of the compressor through the third stop valve, and the second end of the first indoor heat exchanger is connected to the suction port of the compressor through the fourth stop valve;
• and
• a second type indoor unit, in which a second indoor heat exchanger, a second throttling element, a fifth stop valve, and a sixth stop valve are respectively arranged, wherein, a first end of the second indoor heat exchanger is connected to a second end of the outdoor heat exchanger through the second throttling element, a second end of the second indoor heat exchanger is connected to the exhaust port of the compressor through the fifth stop valve, and the second end of the second indoor heat exchanger is connected to the suction port of the compressor through the sixth stop valve.