With the advancement in proteomics research and yearly introduction of numerous environmental contaminants into the soil, development of biomarkers to detect contaminant-responsive proteins in model organisms is receiving increasing attention. Earthworms are the largest group of invertebrates in soil; they are a good model system for evaluating ecological soil pollution. Therefore, detecting contaminant-responsive biomarkers and elucidating the ecotoxicological mechanism in earthworms by using proteomics is of important practical significance. The protein expression profiles of earthworms subjected to several specific pollutants have been investigated. These proteins are associated with many biological processes such as signal transduction, glycolysis, energy metabolism, and chaperone and transcriptional regulation and can be used to determine the possible ecotoxicological mechanisms of relevant contaminants and as potential biomarkers for monitoring toxic contaminants. However, their specificity needs to be determined. In this study, we provided a brief overview of the protein expression profiles and identified potential biomarkers in earthworms subjected to pollution stress.