Design and R&D (Research and Development) of products play an important role in development and competitiveness of enterprise. How to do the works better? We think that most advanced product design methodology should be used on design, research and development of products. So-called most advanced product design methodology is that based on “the Scientific Outlook on Development” that we set up recent years. New developments of product design methodology include: At first it has been classified that more than seventy theories and methods proposed by domestic and overseas scholars in recent 100 years; QCTES was instead of IQCTES including six requirements of product design; traditional design stages were replaced with four new stages including investigation, planning, implement and inspection; green design was replaced with harmonious design; traditional design method was replaced with deep-layer design method; concept and connotation of product top-layer design were proposed; more detailed contents of product systematic design were advanced; formulas of complete system and product design quality, and connection equation between design objective, design content and design method were submitted. We got good effects to apply above product design methodology on many product designs recent years.