Abstract: This paper examines the multimedia environmental behavior of three kinds of organochlorine pesticides,p,p’-DDT、p,p’-DDE、p,p’-DDD in a bay of Hainan,China.A fugacity level Ⅲ multimedia environmental model is used.The model results indicate that the concetrations of p,p’-DDT in air,water and sediment are(0.019 8)g/m~3,(0.016 8)ng/L,0.313ng/g,respectively;p,p’-DDE is(0.019 9)g/m~3,(0.0016 5)ng/L and 0.124ng/g,respectively;p,p’-DDD is(0.0019 8)g/m~3,(0.004 68)ng/L,(0.083 2)ng/g,respectively.Sediments are the most important sinks,which accumulate to more than 99% of the total organochlorien pesticides.The transfer mass of p,p’-DDT,p,p’-DDE,p,p’-DDD are also calculated.The results show that transfer processes on interfaces of the water-sediment and sediment-water are the primary routes for organochlorine pesticides.