Vocabulary learning and teaching has been one of the main issues in ESL/EFL learning and teaching research. EFL teachers in China, in particular, are grappling with the effective vocabulary teaching methods. This paper is doing part of this job in a different way. It discusses three principles based on Cognitive Linguistics (CL), namely the study of categorization, prototype, and metaphor, and implications of these principles in formal vocabulary instruction in a Chinese context of English learning in South-western mainland China.