Abstract: Scientific management and maintenance are important prerequisites for extending the service life of the liquid chromatograph and obtaining good analytical data. By observing pressure conditions during the operation of the instrument, the location of faults can be quickly determined. Taking the widely equipped Waters e2695 liquid chromatograph as an example, focusing on the abnormal pressure faults, the common causes and troubleshooting methods for faults in three aspects were discussed, including system pressure loss or low pressure, system overpressure, and irregular or large fluctuations in system pressure. This providing a reference for the use and maintenance of liquid chromatograph.