Abstract: A lubrication and wear condition monitoring system is designed for the natural gas pressurization units in the long-distance natural gas transportation in accordance with the structure and operation characters of the unit and the new development of the fault diagnosis technology.The lubricant monitoring index serials are also set-up in terms of the common lubrication conditions of the pressurization units.Then the svstem is applied to the condition monitoring tests on the typical imported natural gas pressurization units.The diagnosis standards by used-oil analysis is established based on the monitoring experiences.Typically, the faults of the pressurization units in a station are checked-out by combining the used-oil analysis with the vibration analysis.of which the fault causes and mechanisms of the No.1 unit is analyzed and the correct measures are also suggested.