Detailed measurements of three Zhuganpo Formation sections in the southwest Yangtze Platform suggest that the Zhuganpo Formation needs to be redefined. The redefined Zhuganpo Formation, as represented by the Banqiao section in Luoping County of Yunnan Province, is composed of the lower microlami- nate micritic limestone and the upper medium- and thick-bedded nodular limestone. We propose that the boundary between the Zhuganpo Formation and the Yangliujing Formation should be moved 15. 5 m downsection at the stratotype section and be demarcated by a paleokarst surface atop brecciated dolostone of the uppermost Yangliujing Formation. Conodont biostratigraphy indicates that the revised Zhuganpo Formation is of late Middle Triassic Ladinian to early Late Triassic Carnian age. The Xingyi fauna in the microlaminate micritic limestone of the lower Zhuganpo Formation is late Ladinian in age.