Two-component dark matter : How to get the hint at collider?

We investigate ways of identifying two kinds of dark matter (DM) component particles at high-energy colliders. The strategy is to notice and distinguish double-peaks(humps) in the missing energy/transverse energy distribution. The relative advantage of looking for {\em missing energy} is pointed out, in view of the fact that the longitudinal component of the momentum imbalance becomes an added input. It thus turns out that an electron-positron collider is better suited for discovering a two-component DM scenario. Furthermore, using Gaussian fits of the distribution histograms, we develop a set of criteria to evaluate the distinguishability of the two-peaks quantitatively.