This study analyzes interviews, observations, and documents to explore eight Taiwanese elementary school English teachers' beliefs and classroom practices regarding the alternative curriculum, the school-based curriculum of alternative learning required courses under Taiwan's 12-Year Basic Education plan. A conceptual framework on curriculum innovation based on empirical studies is proposed and the study has the following conclusions. A lack of congruence between government intention and the delivery in classrooms in pilot schools occurs due to English teachers' beliefs. Four major problems are raised during the design and implementation of the alternative curriculum, including teachers' conflicting beliefs about subject matter content knowledge, curriculum knowledge, language for instruction, and assessments. Trainings and professional learning for fostering teachers' professional identity and competence are recommended for effective designs and implementations of the alternative curriculum.