Turner and Hopper's theories on school system and the typology of educational system have been used to analyze Taiwan's educational system; The form and the ideology of implementation of Taiwan's educational selection system will be the focus. In addition, the conventional wisdow supposes a liberal educational system will increase the rate of social mobility, therefore, the relationship between Taiwan's educational selection system and social mobility will be investigated. School system in Taiwan has been an Anerican model. However, American ideologies on education, such as egalitarianism, achievement-orientation and universalism, were not really popular in Taiwan in the past. One reason could be nosuffivient financial resources to support the mass education; the traditional elitist ideology could be another reason. However, in the last decade, there are a lot reforms in Taiwan's educational system, such as increasing the flexibility of school system, adopting multiple strategies in student recruitment. It seems Taiwan is moving towards a more egalitarian educational system. However, the centralized educational system is still expected to release power to do more reforms. With regard to the educational selection system and social mobility, Taiwan cames across the same problem with other countries, that is the solution of the issue of social inequality should be worked out by economic, social and educational sectors together.