Soil urease activity (URE) was usually put forward to indicate the soil fertility. Former studies in other regions had shown that soil urease activity was an indicator for soil fertility, and more urease activity means more fertile. In karst region, the growth of vegetation may be limited by nitrogen element in earlier revegetation. Compared with most other regions, soil nutrients of karst are higher. Therefore, this study aimed to explore the relationship between soil urease activity and nutrients, and find the main factors that affected soil urease activity. An experiment was designed to compare the distribution of soil nutrients under three mainly vegetations to the original forest. In order to explore the value of soil urease anctivity for different vegetation types and its controlling factors, the soil samples of topsoil (0-15cm) were collected in two typical karst peak-cluster within four vegetation succession stages (grassland, shrubland, plantation forest, original forest) in northwest Guangxi, southwest China. A total of 202 samples were collected from twelve sampling lines (each vegetation type had three sample lines for comparison), including 48 grassland samples, 46 shrubland samples, 44 plantation forest samples and 64 original forest samples. Analysis of variance (ANOVA) was utilized to analyze the differences of soil urease activity for different vegetation types. The results showed that there were significant differences of soil urease activity during different vegetation succession stages. Soil urease activity of grassland was the highest, while original forest was the lowest. It indicates that soil urease activity did not increase with vegetation succession. Many influencing factors affected the soil urease activity at the same time, such as TN, AN, soil microbial biomass, clay content, C/N, AN/TN and so on. There was a positive correlation between TK, clay content, bulk density, C/N, AN/TN and URE (P<0.01); whereas negative correlation between SOC, TN, AN, soil microbial biomass and URE (P<0.01). The result was different from most areas in China, such as Beijing, Shanxi, Hunan and so on, but in the area of high TN, the result was the same as ours. Our study indicates that it is not all regions of the urease activity were positively correlated with SOC, TN, AN, and siol microbial biomass. The URE was possible to be negative correlation with main nutrients in regions that N is no longer a limiting factor for crop growth. Therefore, the demand for crop growing is a stationary extent. Even if peopele provide more N nutrient, the enzyme won't decompose the excess part to available nitrogen. Additionally, it is dangerous to nitrogen loss and ammonia volatilization.