During the past two decades, Chinese clothing industry has made remarkable progress in production and export. China has become the world's largest clothing producer and exporter. However, it still falls behind traditionally strong competitors like Italia in term of quality and unit price. Based on industry research on international competitiveness, this paper first constructs an evaluation index system to assess the international competitiveness of clothing industry between China and Italy. To discuss their own competitive advantage origin, this paper applies the Porter's diamond model to compare the key factors affecting their international competitiveness, and finally puts forward measures to enhance the international competitiveness of Chinese clothing industry.