The invention discloses a steel bridge fatigue evaluation 
load modeling and fatigue evaluating method. The steel bridge fatigue evaluation 
load modeling and fatigue evaluating method comprises, step one, establishing a 
train load model; step two, 
processing and classifying measured data; step three, according to the measured data, establishing a 
probability model for parameters; step four, establishing a 
train load 
probability model; step five, generating a random 
load spectrum through a Monte-Carlo method; step six, through finite 
element analysis, acquiring stress influence lines of steel bridge fatigue details; step seven, performing 
influence line loading through the random 
load spectrum to obtain a stress history; step eight, analyzing the stress history to evaluate steel bridge fatigue. The steel bridge fatigue evaluation 
load modeling and fatigue evaluating method has the advantages of, through the fatigue evaluation 
load model which is established on the basis of the measured data for describing the load status of currently-running trains, achieving fatigue evaluation of any component of a steel bridge, establishing a complete 
train load modeling method, improving the utilization value of the measured data and ensuring more accurate and more practical steel bridge fatigue evaluation.