This article traces back to the initial necessity of morals clauses, figuring out the nature and feature of morals clauses by analyzing classic precedents in the United States and in Taiwan. Besides, by comparing the Uniform/Standard Player's Contract of "Big Four" and the Player's Contract of Chinese Professional Baseball League, this article also provides arbitrators and judges with a relatively equitable standard of review to balance, in particular, the unequal bargaining power between the Business and the Professional Athlete. Also, this article is eligible to be the reference for Clubs/Sponsors and Players/Endorsers to equally negotiate foreseeable and enforceable morals clauses that are authentically considering the interests of both parties.