A variable refrigerant volume system and control method thereof. The variable refrigerant volume system comprises: a compressor (1); a four-way valve (19); an indoor unit; a liquid tube (22), the first end thereof being connected to the indoor unit, the second end thereof being connected to the third valve port of the four-way valve (19), and a condenser (18) being provided on the liquid tube (22); a low pressure air pipe (23), the first end thereof being connected to the indoor unit, and the second end thereof being connected to the fourth valve port of the four-way valve (19); a refrigerant adjustment tank (6), the first port thereof being connected to the liquid tube (22), the second port thereof being connected to the low pressure air pipe (23), and the third port thereof optionally communicating with the liquid tube (22) or the low pressure air pipe (23). The refrigerant adjustment tank (6) provides refrigerant to the variable refrigerant volume system when the system requires more refrigerant, and recycles refrigerant from the variable refrigerant volume system when the system requires less refrigerant. The variable refrigerant volume system can flexibly control a refrigerant recycling amount in accordance with a refrigerant operation situation, thus ensuring system reliability.