Air-conditioner capable of using flammable refrigeration agent

An air-conditioner capable of using flammable refrigeration agent comprises an outdoor machine and an indoor machine. More than one concentration detectors used for detecting concentration of the flammable refrigeration agent are arranged inside or vicinity of the outdoor machine. In according to safety requirements of a split air-conditioner using the flammable refrigeration agent, concentration detectors used for detecting the concentration of the flammable refrigeration agent are arranged at a plurality of positions of the outdoor machine, solenoid valves are arranged at a plurality of pipes of the outdoor machine, corresponding valves are adjusted through monitoring of refrigeration agent concentration of relative parts of the outdoor machine. When leakage occurs, leakage amount of refrigerant is minimized, safety of the outdoor machine is guaranteed. The air-conditioner capable of using the flammable refrigeration agent is simple and reasonable in structure, and safe and realizable in usage.