Longchuan county is situated at East Longitude 97 ° 39 '~ 98 ° 17', and between North Latitude 24 ° 08 '~ 254° 39', general elevation is 900 ~ 1500 meters. The annual average temperature is 18.8 ℃, and its annual average rainfall is 1600 mm. It has typical South Asia tropical climate of "no cold winters, nor hot summers." and abundant sunshine which fit into the growth of rape. Dehong has had over 40 years’ history of rape planting since 1960s, and now reaches the dimensions of planting areas 60,000——80，000 mu perennially, standing in the third after sugarcane and paddy. The production value of rapeseeds occupies 5% of the gross agricultural value.
Rape growth has become the key of agricultural development in winter and an important source of farmers’ earning increase of Longchuan.