It is nearly half a century since the Guangdong Dabaoshan polymetallic mine has been exploited.Because of its unscientific process mode of the tailings,the acidic waste water leached out from solid wastes carrying a lot of heavy metal ions flows into the downstream river,which brings great harm to the ecological environment and agricultural activities of downstream area.We investigated the characteristics of distribution change over time of heavy metals` concentration by collecting Dabaoshan downstream paddy soil samples.The concentration of heavy metals(Cd,Cu,Pb,Zn,Ni)in all soil samples was determined by Inductively coupled plasma mass spectrometry(ICP-MS).When compared our data with previous,the results show that: With the time passed by(nearly about ten years),the Pb,Cd and Ni concentrations are relatively lower than before in this area,but the decline is different.The decline percentage of Cd concentration is relatively bigger,but still higher than the environmental standards,which may be associated with the replacement of mountain spring irrigation by local people.The concentrations of Cu and Zn showed a trend of increase,and even up to four and fifteen times higher than the environment standard respectively.So the local ecological environment,agricultural production and human health are still having a greater risk.