Abstract: Sample plot investigation method was conducted to survey the ant populations and species diversity under four types of vegetation in Zijin Mountain in Nanjing. 4 052 specimens which belonged to 2 subfamilies, 14 genera and 15 species were collected. Comparative results showed that species number of 14, species diversity index of 2041 6 and evenness index of 0773 6 were the highest in the coniferous and broad leaf forest, the dominance was only 0158 8. The dominant species of ants were Camponotus japonicus Mayr (2480 %), Pheidole nodus Smith (1798 %), Pristomyrmex pungens Mayr (1757 %) and Paratrechina flavipes (Smith) (1431 %). Ten species of ants were collected from grassland. The diversity index and evenness index were 1.147 5 and 0.498 4 respectively. They were the lowest among these four vegetations. The dominance index was 0413 4 only next to the dominance index of 0415 1 in broad leaf forest. The dominant species were P. pungens Mayr (5413 %) and P. nodus Smith (3427 %).The ant populations similarity of the four vegetation types were in medium degree in Zijin Mountain area.