Cross-sectional survey from September to December 2009, the object are the ethnic minority t women 15-49 years old, in the area of 4 provinces: Cao Bang, Son La, Lai Chau and Yen Bai, to describe knowledge about HIV/AIDS of the ethnic minority women 15-49 years old in these provinces, from that point to propose the interventional, preventive models or appropriate measures. The results are 1520 people who were interviewed. The highest rate are women aged from 20 to 29 (38.9 percent) and from 30 to 39 years (31.6 percent). On education level: university/college 4.7 percent, secondary education 25.2 percent, secondary basis 42.2 percent, primary 21.2 percent and illiterate are 6.7 percent. More than 93.0 percent of ethnic minority women can read fluently the popular language. The average age of first sexual intercourse is 18.0 (17-19). The rate of condom use is low: 9.4 percent of them answer that they use a condom during "most recent" sex with husband/lover and 2.5 percent always use condom all times during sex. There are 9.1 percent of women have sex with casual partners, among them only 11.1 percent use a condom during "most recent" sex and 4.4 percent frequently use condom. The ethnic minority women's a full understanding of the transmission and prevention of HIV/AIDS is only 11.5 percent. The percentage of women who self -reported symptoms of the sexually transmitted diseases and sores in genital area are respectively 16.3 percent and 12.7 percent.