All-terrain vehicle(ATV) is very popular in Europe and North America because of its excellent riding performance. The Design of suspension and steering mechanism is one of the most important parts in ATV design, because it is much related to the riding performance of ATVs. Therefore, this research focuses on investigating the design of suspension and steering mechanism for ATVs. There are two main objectives to be achieved in this research. One is to build the analysis theory, and the other is to develop a systematic design process of suspension and steering mechanism for ATVs. Firstly, we survey papers about suspension and steering mechanism to find its basic functions and properties. Secondly, we use engineering design method to classify the design requirements and frame the design process. Thirdly, we list new suspension and steering mechanisms by applying the creative mechanism design procedure, then separate the new mechanisms separate into two types. One type is suitable only for back-wheel drive vehicles, and the other type is suitable for back-wheel drive and four-wheel drive vehicles. Finally, we complete the kinematic design of the type1.1(double-wishbone) and type8.3(new mechanism) suspension and steering mechanisms based on the Genetic algorithm (GA), and we can obtain the better mechanism dimensions than Yamaha 660 and 450 ATV.