A study was carried out to study the accumulative levels and dynamic changes of organochlorine pesticides in human milk in Beijing from 1982 to 1998, and the effect of prohibition and restriction on the use of DDT and BHC (666) in China in 1983. The milk samples were collected from women during the lactation period in four districts of Beijing from 1982 to 1998, in 1991, 1993 and 1998, respectively. The contents of DDT and BHC in human milk were determined according to the standard method of biology-monitoring of PR China. The average fat content of human milk was about 3% from 1982-1998 in Beijing. The average concentration of pp-DDT and op-DDT in 1985 was less than 0.10 mg/kg and remained so until 1998. The average concentration of pp'-DDT decreased from 1.80 mg/kg in 1982 to 0.24 mg/kg in 1998 and that of pp-DDE descended from 5.87 mg/kg to 1.72 mg/kg and the total concentration of DDT dropped from 7.71 mg/kg to 2.04 mg/kg. Since prohibition of organochlorine pesticides 1983, the average concentration of beta-BHC and total BHC fell respectively from 9.66 mg/kg and 10.1 mg/kg in 1983 to 1.18 mg/kg in 1998. However, the accumulative concentration of DDT and BHC was much higher than that of some foreign countries. Therefore, it was important and necessary to monitor organochlorine compounds in human milk continuously.