Synonyms are usually hard to distinguish even for native speakers, such as (1). They would cause Mandarin learners to avoid using or to misuse ”yīnwèi” and ”yóuyú”, such as (2). The aim of the study was to distinguish between the two synonyms. We analyzed the usages and functions of ”yīnwèi” and ”yóuyú” from ”Chinese Word Sketch”. We examine the syntactic behaviors and lexical semantic properties that differentiate the pair of near-synonyms ”yīnwèi” and ”yóuyú”. Results indicated the differences between their co-occurrence. We observed them through Chinese Word Sketch, and quantify the statistics of their data. The study would provide a systematic way to distinguish the synonyms. (1) a. {yīnwèi/yóuyú} rènshŏu bùzú, suŏyĭ gōngsī juédìng zài qĭng jĭ míng gōngdúshēng lái bāngmáng. b. dàjiā de yóuyŏng chéngjì míngxiăn tíshēng, shì {yīnwèi/yóuyú} jiàoliàn de nàixīn zhĭdăo. (2) a. tā zhèjĭtiān xīnqíng bùhăo, {yīnwèi/*yóuyú}tā de àiquăn zài shànggèyuè zŏu diū le。 b. {*yīnwèi/yóuyú} wŏ de gōngzuò guānxì,yìncĭ zài Gāoxióng dòuliú le jĭtiān.