The study on the flora of six nature forests shows that the composition of plant species is abundant in the nature forests of Niumulin nature reserve zone, there are 248 species of high plants in 2900 m2 area, which belong to 153 genera in 82 families. Among them, 16 species of 14 genera in 11 families are pteridophte, and 3 species of 3 genera in 3 families are Gymnosperm, and 229 species of 136 genera in 71 families are Angiosperm. The coefficient of genus is 61.69. On the distribution pattern of gunus, the tropic distribution pattern is the main floristic element. 63.36% of the genera in the nature forests belongs to tropic, and 32.82% of the genera belongs to temperate, which shows the geographical characteristics of Niumulin nature reserve zone that lies in northern edge of South Subtropical Area.