Abstract: In the past, academia paid much attention to the similarity between komatiites and picrites, but ignored their differences. In this paper, the global data of Archaean komatiites and Post-Archaean low/high titanium picrites in the database were collected by full data model. Based on comparing the differences between them, the authors found that komatiites are richer in MgO, Cr, Ni, Cs, Pb, Co and Zn, followed by low-titanium picrites (except for Co and Zn). As for the other main and trace elements, high-titanium picrites has the highest content, followed by low-titanium picrites and then by komatiites. Based on the differences between elements such as Cr/Ga, MgO/Ga, MnO/Zr and Cr/Zr, the authors used density distribution to draw an isodensity discriminant map which can effectively distinguish the three types of rocks, and redefined the lithology of some Late Paleozoic "komatiites" with this diagram. The results of lithofacies and geochemical characteristics show that, in the Late Paleozoic "komatiites", the rocks in the eastern part of India are high-titanium picrites, those in Vietnam are low-titanium picrites with similar chemical composition to komatiites, and those in Ladak area of India are low-titanium picrites.