Form, as a component of the product, is the key point that directly affects the visual expression of the product in product modeling design. For the product which needs to close contact with the human body, its Ergonomics Form and function have deeper interactions with each other, and the form often has the function of supporting. From the point of view of ergonomics, this paper focus on the car seat Man-machine From design, through the relevant experimental research and comfort questionnaire survey. It is found that those products which have more superior ergonomics form design, can provide users with more creature comforts.