The current situations of lack of brands, weak market, weak technologies and weak core competitiveness in China can be changed through product design innovation. Design innovation method is the key to product design. Taking the product design innovation method based on systematics theory as study content,theoretical research problems of product design innovation method are put forward,the laws of product design innovation method in systematics theory are explored. The study will promote systematic innovation of product design. It is concluded that product design innovation is a complex systematic innovation,it needs creative idea,innovation theory and innovation tools,meanwhile, the function innovation,technological innovation,and art innovation are necessary.