Field investigation was conducted in order to assess topsoil trace element contents and the factors influencing topsoil trace element variability in the intensive periurban area in Dianchi Lake watershed,Yunnan Province,in south-western of China.Soil texture varies from loam in the lacustrine unit(L) to clay in the transition unit(T),then to heavy clay in the mountain unit(M).Soil colour is brown,and darker near the Lake and redder in the mountain unit.The mean Pb,Cd,Cu and Zn contents in topsoil are 56.7,0.47,125.7 and 114.2 mg· kg-1,respectively.Total Pb,Cd and Zn mean contents in topsoil are low contaminated level(Pi of Pb,Zn and Cd ＜2) and total Cu medium is contaminated level(Pi of Cu ＞2).The pH,SOC and CEC are the principal components influencing soil trace element contents.Variation in Pb could be affected by SOC,Cd by SOC and CEC,while Cu by CEC.From north-east to south-west,contents of Pb,Cd and Zn are from high to low(M ＞ T(L)for Pb,M ＞ T ＞ L for Cd,Cu and Zn),which is consistent with elevation gradient.The factors influencing trace element contents in the research area are SOC,CEC,morphological factors(relief and soil parent materials) and non-pedological factors(pesticides,fertilizers,irrigation and road traffic).