Mistranslation in Lin's translation is universal and controversial. In addition to translation, Lin Shu was able to write and paint, which helped construct his multiple roles as a scholar of classical Chinese, writer, painter and so on. From the perspective of translator's role shifting, this paper reinterprets Lin Shu's multiple roles and the generation mechanism of his mistranslation from such aspects as narrative techniques, ethical values, and visual aesthetics in Bing Xue Yin Yuan. It is stated that Lin Shu's multiple roles interweave and complement each other, contributing to his various mistranslations. The study of translator's role shifting is helpful to account for Lin Shu's multiple adjustments and transformation of the target text, and to explore his nature as social being and the socialization of his translation more comprehensively and objectively.