Abstract: Species richness is an indicator of species diversity. It is of great significance to study the relationship between species richness and environmental factors on the development, planning and management of nature reserve.Nineteen nature reserves in Guangdong province with detailed background data were selected for this research.Relationship between the species richness (number of family, genera and species) and environmental factors (longitude,latitude, altitude, annual average temperature, frost free period, the average annual rainfall, relative humidity, the area) was analyzed. The results showed that the species richness was negatively correlated with longitude, and positively correlated with altitude.