Abstract:This paper studied the distribution of the heavy metals including As, Cd, Cr, Cu, Pb, and Zn in the paddy soils of Hani Terrace core zone, which is comprised of four sections, Niujiaozhai River patch, Malizhai River patch, Amengkong River patch, Dawazhe River patch. Means of heavy metals in the soils collected from four zones were compared with the background values (BV) of soil heavy metals in Yunnan Province. The results show that the average content of Cd in sampled soils was a little higher than the BV, the average content of Cr was more than 2 times of BV, and the average contents of As, Pb and Zn were lower than BV. The difference of heavy metal was not obvious between different sample sites (patch). Due to Cu mine in Niujiaozhai zone, the content of Cu there was much higher than and those in other zones and the BV. Correlation analyses indicate that acid soil of wetland affected the activity of Cd greatly. High organic matter and total nitrogen play an important role in improving accumulation of Pb and Zn in soil. There was a similar distribution of Pb and Zn in four zones. This may be attributed to similar parent materials of soil, pattern of cultivation and human disturbance. By using the Hakanson′ method of potential ecological risk assessment, the potential ecological risk of heavy metals were estimated. The result show that the potential ecological risk of Cd in four zones was up to moderate, which of Cu was moderate in Niujiaozhai River patch and light in other patches. Moderate potential ecological risk region may occur in Niujiaozhai River patch, stressed by Cu and Cd heavily and As, Cr and Pb, Zn slightly. The potential ecological risk in other three patch was light with the order of risk as follows Amengkong River patch > Dawazhe River patch > Malizhai River patch. In these patches, Cd was the major ecological stressor, followed by As, Cr and Pb, Zn.