Abstract Recently fishing industry in Taiwan is under hugely severe business environment. Due to distinctness of diplomatic situation, it is totally different competitive situation Taiwan is facing. Therefore, not only development of ultra-low-temp tuna fishing industry and managerial means and of international or regional incubate organization will be deeply described but also diamond model of Porter will be explored to analyze the competitive advantages of ultra-low-temp tuna fishing industry of Taiwan in the thesis. Definitely, the conclusion will used to develop practical plans for future severe situation. After well understanding literature about development of ultra-low-temp tuna fishing industry in Taiwan, I concluded the followings based on perspective of diamond model: 1. The first is that operations of Taiwan Tuna Association and cluster effects build the competitive advantages other countries are hard to get beyond. 2. Secondly, under relatively stable variation of tuna prices, the fishing boat owners are emphasizing on cost reduction in order to maintain business operations and get above average earnings. The ability of cost control is competitive advantage of fishing industry of Taiwan. Keywords: diamond model ,ultra-low-temp tuna fishing industry ,competitive advantage