Based on the geochemical property and the discrimination principle, we used the data of Th, Nb and Zr of basalts formed from typical tectonic setting of the world, studied the geochemical identification principle of tectonic setting of basalt using Th, Nb and Zr, and found that the characteristics of Th, Nb and Zr of basalts in different tectonic settings had evident difference. The ratios among Th, Nb and Zr could divide the type of tectonic setting where the basalts were derived from their mantle source. The paper proposed the tectonic settings Nb/Zr-Th/Zr ratio discrimination diagram of the basalts in the convergent margin of plate. The diagram could not only divide the collision zone of ocean-ocean, the collision zone of ocean-continental and the collision zone of two continental plates at the margin of convergent plate, but also reflect the evolutional trend of tectonic setting of island arc basalts.