Several different subjects were involved and many factors should be taken into account in the design of seats system, the basic principle of ergonomics was the most critical factors. Based on the sitting behavior and function of human, theoretical analysis on the sitting and the classification of seats system are carried out, and the design details of every part in all kinds of seats are proposed. Based on the basic principle of ergonomics and design details of seats system, the design on a "portable, solid wood and collapsible rest seat" with the characteristic of the beauty, suitability, the comfortability have been carried out.