A sliding mechanism for portable electronic device includes a sliding housing, a main housing and a stopping module. The sliding housing includes two ledges. At least one of the ledges defines a first notch and a second notch. The main housing includes two rails and at least one elastic member. The sliding housing is slidingly attached to the main housing by engagement of the ledges and the rails. The at least one elastic member includes a positioning portion. The positioning portion flexibly resists the at least one of the ledges and is selectively engaged in the first notch and the second notch. The stopping module prevents the sliding housing from separating from the main housing.