Bridge plays an important role in modern transportation. Once it is damaged, there will be great loss. So assessment of bridge state has become more and more important in modern society. Ambient around bridge always are very complex and bridge is affected by many factors. So in all response of bridge, noise and useful signals mixed together. The noise generally includes temperature effect, wind load effect, live-load effect, and so on. In order to get the useful signals we must separate the live-load effect from the total effect by using multi-scale analysis firstly. EMD brought a new method for multi-scale analysis and it is superior to wavelet to some extent. But it has some shortcomings also. In order to improve the performance of the EMD further, EEMD is introduced to extract live-load effect of bridge. The practical and simulation results verified the feasibility of the new method based on EEMD and the results is much better than those based on wavelet.