A slide rail assembly includes a rail element, a first bracket, an extension frame, a second bracket, a blocking element, and an elastic element. The first bracket is mounted to the rail element and configured to be mounted to a first post. The extension frame is movable relative to the rail element. The second bracket is mounted to the extension frame and configured to be mounted to a second post. The blocking element is movably connected to the second bracket. The elastic element is configured to provide an elastic force to hold the blocking element at a first position relative to the second bracket. When the extension frame is driven by the rail element to move along a direction, the extension frame pushes the blocking element to rotate from the first position to a second position, such that the second bracket is detachable from the second post.