Objective To observe the prevalence tendency of soil transmitted nematodes infections in Min County,Gansu Province during 2006-2010 through constant surveillance on the population and soil samples detection,thus to provide evidence for making strategy of disease prevention and Control.Methods 1000 persons were investigated to find soil transmitted nematodes by sentinel surveillance.Eggs of A.Lumbricoides and T.trichiura were examined by Kato-Katz technique(3 thick smears per sample)while eggs of A.Lumbricoides examined for soil contamination in 10 families with saturate sodium nitrate floating method.The infection rates were compared among the five years.Eggs number of A.lumbricoides from soil and A.lumbricoides infection level of the families were obtained,then correlate analysis was applied.Results Soil transmitted nematodes infection rate in the population decreased from 20.31％ to 11.08％ in the five years,relative decreasing ratio was 44.26％.In the age group of 0-15,the infection rates were higher than those of older groups.The population with high infection rate was children live scattered,preschool children and students,respectively.Using correlate analysis by one side t test,number of soil A.lumbricoides eggs in the living environment and infection level of A.lumbricoides in those families had positive correlation,which indicated statistically significance exists (t =4.40,P ＜ 0.10).Conclusion The infection rate of soil transmitted nematodes decreased significantly during 2006 to 2010 in Min County,but still prevailed with low incidence rate in the area.