This dissertation examined the effect of year-long study abroad program on the development of intercultural sensitivity among the Mainland Chinese high school students. The sample consisted of 50 study abroad participants and 50 students on home campus. The instrument Intercultural Development Inventory (IDI) was employed to assess the intercultural sensitivity level of Mainland Chinese students before and after study abroad experience. The paired samples t-test results reveal that study abroad students did not make statistically significant gains in the overall intercultural sensitivity through participation in the year-long study abroad program. Although there were statistically significant differences in the posttest ethnorelative scales between study abroad students and students on the home campus, the study abroad students did not make significantly greater progress in their overall intercultural sensitivity between the pretest and posttest than the comparison group. The regression results indicated that the independent variable of total amount of previous intercultural experience significantly contributed to the development of intercultural sensitivity.On average, study abroad students participants were in the stage of Minimization as measured by IDI prior to study abroad and remained at the same stage by the conclusion of the study abroad experience. The findings imply that the study abroad program needs to provide support to increase students’ skills and sensitivity so that they can deal effectively with cultural differences.