A variable refrigerant flow (VRF) system, which includes: a first outdoor unit, the first outdoor unit at least including three external interfaces, namely, a gas-side stop valve, a liquid-side stop valve, and a multi-functional pipe stop valve; a first indoor unit, two ends of a refrigerant pipeline of the first indoor unit being respectively in communication with the gas-side stop valve and the liquid-side stop valve; and a replaceable module, one end of a refrigerant pipeline of the replaceable module being in communication with the multi-functional pipe stop valve, and the other end being in communication with the liquid-side stop valve.