A locating structure for a slide assembly operates in conjunction with a middle, an inner, and an outer rail with the inner rail sliding into the middle rail and the middle rail sliding in the outer rail and includes a linking member, a locating member and an elastic member. Both the linking member and the locating member are pivotally connected to the middle rail. A first protruding wall containing a blocking portion and a slope is disposed on the inner rail. A second protruding wall containing a retaining portion and a slope is disposed on the outer rail. The linking member includes a constraining end and a release end. The locating member includes a release end and a fixation end. The elastic member is fixed to the middle rail to hold against the release end of the linking member and the fixation end of the locating member.