Xenograpsus testudinatus is a dominant species in shallow hydrothermal vents off Kueishan Island, Taiwan. But we know little about crab populations in vent areas. In this study, stable isotope and one dimension protein expression profiles were studied to evaluate the differences of X. testudinatus from different habitats, i.e. white and yellow vents. Results indicated food sources between the two habitats were different in 2009, but similar in 2010. The ranges of £_15N value of X. testudinatus were broad which might result from abundant food in white vent. Furthermore, zooplankton might not be the major food source of X. testudinatus. Significant difference in protein expression profiles between habitats indicate that they adapt to different habitats in small scales with migration between habitats. And, crabs may have other habitats outside vent areas. After culture in laboratory for 12 hours, crab protein expression profiles were different from their original ones, indicating their acclimation to a new environment is relative fast.