An adjustable fence comprises two opposite posts, a slat assembly, and two buffering elements. The slat assembly has multiple detachable slats detachably mounted between the posts. The buffering elements are respectively mounted in the mounting slots of the posts, and each of the buffering elements is disposed between the post body of each of the posts and the slat assembly. Increasing or decreasing the detachable slats of the slat assembly adjusts the height of the adjustable fence for different applications. The pushing force resulting from the thermal expansion or/and contraction of the slat assembly or/and the post body is absorbed by the buffering element, so that the bottom bracket of the slat assembly and the post body do not push each other to be deformed.