The invention relates to a failure monitoring and predicting method and 
system of 
power equipment. The method comprises the following steps: (1) installing a failure monitoring and predicting 
system comprising a 
reciprocating engine, an oil extraction device, an oil 
preprocessor, an oil data analyzing and storing module, a 
failure diagnosis module, a magnetoelectric sensor, a 
voltage sensor, a 
pressure sensor, a temperature sensor, a 
vibration sensor, an ultrasonic wave sensor, a 
signal conditioning box, an analog-to-
digital conversion module and a 
data acquisition module; (2) the 
data acquisition module acquiring the 
crankshaft phase 
signal and each sensor starting acquiring the signals; (3) sending the acquired signals to the 
failure diagnosis module; (4) the oil extraction device taking out dynamic oil samples and the oil data analyzing and storing module sending the concentration values of the metallic elements in the oil to the 
failure diagnosis module; (5) determining the threshold values of the phase 
signal and the amplitude; and (6) the failure diagnosis module carrying out failure monitoring and predicting on the reciprocating 
machine states. The invention has overall acquisition means, can satisfy the failure predicting and monitoring functions and has high diagnosis precision. The invention can be widely applied to various reciprocating machines.