Internal migration in China has introduced critical challenges to the education and health of migrant adolescents. The aim of this study was to explore the differences in sexual knowledge and attitudes among migrate and local adolescents. Survey research with a total of 616 adolescents in grades equivalent to US 10^th and 11^th grades including 113 migrants completed a selfadministered questionnaire. Misconceptions of adolescent physical development, sexual activity, marriage, birth control, sexually transmitted diseases and the probability of pregnancy were found in most of the migrant adolescents. Significantly lower attitudinal scores were found for the sub-scales of clarity of personal sexual values, understanding of emotional needs, social behavior, sexual responses; attitudes towards gender role, birth control, premarital intercourse, use of force in sexual activity, the importance of family and satisfaction with social relationship in migrant adolescents. Migrant adolescents have a low level of knowledge of sexual activities. The content of education programs should include engagement in sexual behavior to equip adolescents with unbiased and factual knowledge. The adolescents have a high demand for family support. School based sex education programs should involve the participation of parents to address these issues.