The invention discloses a state monitoring and fault diagnosis system of a gas turbine generating unit and a use method of the state monitoring and fault diagnosis system. The state monitoring and fault diagnosis system comprises a vibration monitoring module and a network module of a control system of the unit, a signal acquisition module and a computer which is provided with a LabVIEW platform, wherein a state performance signal is transmitted to the computer by the network module; the signal acquisition device is provided with a signal acquisition circuit and a signal processing circuit; a vibration signal output by the vibration monitoring module is acquired by the signal acquisition circuit, is processed by the signal processing circuit and is then transmitted to the computer; data acquisition is performed after an acquisition channel of the signal acquisition circuit is set by the LabVIEW platform; the LabVIEW platform comprises a real-time analysis module, an off-line analysis module and a fault diagnosis module; on-line monitoring and analysis are performed on the state performance signal and the vibration signal by the real-time analysis module; off-line analysis is performed on recorded data by the off-line analysis module; and fault diagnosis is performed on the unit by the fault diagnosis module. The state monitoring and fault diagnosis system is easy to operate and high in diagnosis accuracy and efficiency and can be applied to state monitoring and diagnosis of each turbine generating unit.