To reduce thenumbers of measuring channels,prepare period and amount of data during the large-scale whole vehicle customer road load measurements,in this paper a method,based on system identification,was described to estimate the cumulative fatigue damage of whole vehicle and components with statistic results of only a few measuring channels. An example of longitudinal wheel cumulativefatigue damage estimation was also given based on small-scale customer road load data of a certain A-level car. With good consistency between the estimation result and the actual value,this method was proved to be feasible and valid.