The CEPA signed between mainland and Hong Kong has made an important promotion on bilateral trade and investment since its implement on 1stJan. of 2004. By last year，mainland provides preferentialtarif tocommoditiesunder1587four digit HSheadings.ARuleoforig inisasetsofcriteria to decide a goods' origin. It safeguards the steady implementation fundamentally. This article firstly introduces the general framework of CEPA and the contents of its rules of origin. Then analyzes its characteristics comparedwithotherregionaltradeagreements. Lastbutnotleast，thearticlediscussesthe impact of the application of its rules of origin.