Abstract: The Lunan Stone forest is the product of multi stage karstification In light of the contact relationships between the stone forest and strata,lithologic change,dissolution rate,paleoweathering crust and ages of the travertine samples,the stages of development of the Lunan stone forest have been determined;they are the pre basalt stage（early Late Permian）,pre Lunan Ancient Lake stage（Triassic Paleocene）,Lunan Ancient Lake stage （Eocene Oligocene） and Plateau Bajiang River stage （middle Pliocene Pleistocene） The last stage was the principal development stage of the pinnacle stone forest The separation and superimposition of various stages of stone forest were the cause for the diversification of the karst landscapes of the Lunan stone forest