The purpose of this article is to research the meaning of a third personacting in good faith in the civil act and the commercial act, bad faith or by grossnegligence and the knowingly to the detriment of the debtor in the act of billsof exchange and promissory notes. In this article, the author brings questionsinto the prevalent theories and judicial precedents which are lack of integrity andconsistency according to the characters and purposes of the civil act, commercialact and act of bills of exchange and promissory notes. The author tries tosuggest that the meanings of “a third person acting in good faith” in the civil actand commercial act and “bad faith or by gross negligence” and “awaring that itwould harm the debtor” in act of bills of exchange and promissory notes shouldbe interpreted and applied consistently and systematically according to thepurposes or characters of the laws related. In conclusion the scope ofprotection in behalf of the third persons in commercial trade should be widerthan that of those in civil trade. And the holder of drafts or checks who isunaware of the detriment of the debtor should be more widely protected thanthe third parties in the civil or commercial trades.