There are two opinions about the construction time of cave 78 at the Maijishan Grottoes: one is that it occurred in the Later Qin dynasty while the other argues in favor of the Northern Wei. By examining painting techniques and procedures, this paper finds that as the extant burnt wood braces and paintings in the town of Qiuci were contemporary with the cave rather than overlying, cave 23 was most likely constructed in the Northern Wei dynasty.