This paper briefly discusses the mineralogic and petrologic characterist- tics of potassic lamprophyre in western Sichuan-Yunnan, and its tectonic setting of occurrence as well as the comparison with that in western Austra- lia and Guizhou, China, in order to determine the favorable areas and the prospects of searching for diamond-bearing lamproite on the Yangtze Plate. The diamond-bearing lamproite in western Australia is the product of infra-plate magmatic activity, rich in Ba, K, Rb, Sr, volatile components and light REE, with K20/Na20>10, K20/A1203=1.2, and high content in Ti02. It belongs to the ultrapotassic rock series enriched in K，Ti and Mg, and poor in Al, with high speed of explosion and thus is undifferentiated. The mineral assemblages are of high-pressure facies and low-pressure facies, and no me- drum-pressure facies is found. The diamond-free lamproite in western 'Sichuan-Yunnan is formed as a result of magmatic activity at the plate margin. K20/Na2O=1-5, and K2O/Al203 = 0.22-0.58. Obvioulsly these ratios are low. It belongs to potassic rock series with moderate K and Ti contents and slight A1 and Na satua- tion. Its explosion speed is slow and the mineral facies have the characteris- tics of the evolution from high-pressure through medium-pressure to low- pressure facies. Comprehensive comparison of the lamproite in this area with that in western Australia and Guizhotu, China seggests that the increasing in K，Ti and volatile components is related to both the stability of the plate and the depth of the magma generation. Therefore the diamond-bearing lamproite within the Ya.ngtze plate should be of common occurrence in the southeas- tern peripheral areas of the central Sichuan oldland core.