A series of late Mesoproterozoic to middle Neoproterozoic granitoids are distributed in the western margin of the Yangtze Block, which is an important window to explore the convergence and disintegration of the Rodinia supercontinent. The Huangcaoba granitoid pluton, which consists of gneissic granite, monzonitic granite, and biotite granite, is located in the Xujie area of the Mouding County, Yunnan Province along the western margin of the block. These granites are characterized by high Si (SiO=2 70. 77% ~ 78. 79%), high alkali (Na=2O + K=2O) (7. 15% ~ 8. 73%), high ratio of FeO=T/ (FeO=T + MgO) (0. 70 ~ 0. 98) and 10000 × Ga/Al (2. 68 ~ 6. 84), low Ca (CaO 0. 07% ~ 0. 90%), and low Mg (MgO 0. 02% ~ 0. 88%). Their LREE compositions are relatively enriched and show obviously negative Eu anomalies. Moreover, they are enriched in Rb, Th, U, K, Nd, and Sm, but are relatively depleted in Nb, Zr, and Hf, and are strongly depleted in Ba, Sr, P, and Ti. These geochemical features indicate that the Huangcaoba granitoid pluton belongs to the A-type granite. In-situ zircon U-Pb dating results show that the gneissic granite (1090 ± 24 Ma) and monzonite granite (1063 ± 5 Ma) formed in the Mesoproterozoic with the =ε=Hf=(=t=) values of +4. 3 ~ +10. 3 and =T=DM2= ages of 1. 33 ~ 1. 62 Ga. All lines of evidence suggest that the diagenetic material came from the partial melting of new crusts. The crystallization age of the biotite granite was dated to 782. 4 ± 8. 2 Ma, belonging to the Neoproterozoic period. Their =ε=Hf=(=t=) values vary from -7. 3 to -2. 1, all of which fall below the chondrite evolutionary line. Combined with their =T=DM2 age of 1. 80 ~ 2. 14 Ga, this biotite granite was derived from ancient crusts. Based on the previous research, the Huangcaoba A-type granitoid pluton was generated in a post-orogenic extensional environment during the Mesoproterozoic to Neoproterozoic period in response to the contemporary multi-stage orogenic cycle.