A slide rail structure of relative slide assembly includes two slide guide members disposed on a slide member. Each slide guide member has a locating section connected with the slide member. The locating section has a slide guide section disposed on one side of the locating section, which side is distal from an edge of the slide member. The slide guide section is bent toward the edge of the slide member. Two pivot seats are pivotally disposed on two sides of a relative slide member. A main support is connected on each pivot seat. The main support has a relative slide guide section disposed on the main support and slidable along the slide guide section. The slide guide section is bent over the locating section in an overlapping state. Therefore, the width and volume of the slide guide member are minified to enlarge internal utility space of the slide member.