本研究依循Uggla腳步，從夥伴品牌的角度出發，藉由操弄夥伴品牌的品牌延伸契合度，探討品牌結盟之後，夥伴品牌後續的品牌延伸策略是否會對總體契合度產生影響，進而影響到消費者對共品牌的評價，以告知領導品牌的品牌管理者，在使用共品牌策略時，須謹慎評估日後共品牌策略可能帶來的負面影響。本研究採單組前後測之實驗方法，以Nike+iPod sport kit做爲共品牌實驗產品，並以夥伴品牌Apple推出遊戲機、洗衣機做爲虛擬延伸標的物，發展出兩種高低品牌延伸契合度的實驗情境，並招募了210位受測者，然後隨機分派於兩種實驗情境中。研究發現：(1)品牌延伸的負向回饋效果除了會影響到消費者對母品牌的態度外，亦會影響到對共品牌的總體契合度，(2)品牌延伸的負向回饋效果的影響力勝於正向回饋效果，(3)本研究也擴展了影響共品牌評價因素的範圍，驗證了在結盟之後夥伴品牌的競爭策略，亦會影響到日後消費者對共品牌的評價，進而凡是有損消費者對夥伴品牌的品牌態度之行爲皆會對消費者的共品牌評價產生影響。

This study followed Uggla's research, starting from the perspective of brand partners. After manipulating by brand extension fit of brand partners and discussing the brand alliance, whether the brand extension strategy of the partner brand has impacts on co-brand strategy or not, it will inform the brand manager of the leading brand. When using the co-brand strategy, it must assess the negative influence carefully which the co-brand strategy might bring in the future. We use pre and post test with Nike+iPod sport kit as experimental products and use partner brand-Apple to introduce the launch games or washing machine as hypothetical extensions. We develop two high/low brand extension fit the experimental conditions and collect 210 valid questionnaires by convenience sampling. This study found that the negative reciprocal effect of brand extension will affect the consumer's attitude toward the parent brand and also has impact on the overall fit of co-brand. We also prove the negative reciprocal effect of brand extension influence more than the positive reciprocal effect of brand extension. We also extent the scope of affecting co-brand factor, evaluate the competitive strategy after partner brand alliance will affect the co-brand evaluation of consumers. As well as any partner brand's behavior which breaks the consumer's brand attitude of the co-brand will effect the co-brand evaluation of consumers.