Using geochemical prospecting data obtained in previous geological investigation and soil U, Th and K content data

obtained from 1∶250 000 geochemical exploration in Chengdu Economic Area, this paper predicted the natural radioactivity on the

groundair interface. The results show that the specific activity of the radioactive nuclide  40K is higher than its average

values of China and the world, 238U  is much lower than its average values of China and the world, and 232Th  is equivalent to

its average value of China but much higher than its average value of the world. Except for small areas in Longmenshan folded belt

and EmeishanWashan faulted fold belt, the radiation level of Chengdu Economic Area is within the national limits of radioactive

nuclides in building materials. This paper provides support for the reasonable and effective use of land and resources in Chengdu

Economic Area and also supplies the necessary reference for speeding up economic integration and sustainable development of

cities.