Abstract: According to Polanyi's theory of tacit knowledge, all knowledge consists of both explicit and tacit knowledge, all of which inevitably carry tacit attributes, and writing curriculum knowledge is no exception. Using an adapted version of Goodlad's hierarchical theory of curriculum as an analytical framework, the tacit attributes of writing curricular knowledge embedded in the development, selection and presentation, and teaching of writing curricular knowledge can be revealed at three levels: the ideal curriculum, the formal curriculum, and the practical curriculum. Under the perspective of tacit knowledge, according to the nature and needs of different levels of curriculum, four paths of transforming writing curriculum knowledge can be identified, which are: establishing an authoritative academic research community to enhance the recognition and legitimacy of writing curriculum knowledge development; developing comprehensive standards for selecting writing curriculum knowledge and optimizing the content system of the language curriculum standards to enhance the scientific nature of language textbook development; stimulating students' motivation for writing, guiding students to carry out planned and targeted writing practice; creating an open, interactive and shared writing situation, and establishing a community of writing practice in which teachers and students participate together.