Abstract: This study probes into the semantic extending mechanism and experience on English and Chinese light concept from the perspective of cognitive primary metaphor. The result indicates that light conceptual structure provides reference for the experience and cognition of other concepts, and there are homogeneity and heterogeneity in the extending mechanism of English and Chinese light conceptual metaphor, thus further confirming that different people share the same metaphorical awareness about the world on the common bodily experience and own the free-will ability on metaphorical construction.