It is a general phenomenon that small-sized caves and niches have collapsed or are missing in Longmen Grottoes. Through proper mending and restoring processes, carvings can be protected against damage from sunshine and rain. The conservation work described here, using, as an example, restoration of Cave 683 in Longmen Grottoes, demonstrated the method using a small reconstruction of cave ceiling. There was little change of cave appearance, although the caves were protected. It was also shown that the method could be used to protect outdoor stone relics.