To have an optimal car on the current world's situation, Design and construction of mini vehicles (Class A) are main suggestions of Automotive Engineers. The reason of this suggest is the suitable price and less environmental pollution and traffic than other vehicles. Due to said problems in Iran and the lack of a proportional national vehicle, the need to design and build a Class A vehicle that can help resolve problems is feeling extremely. After design and reach to a general plan of vehicle chassis and body to better performance of this car, some tests envisage on different parts of the car. Static, dynamic and some crash tests on the chassis and body are cases, used to certify, validate and identify its strength and weakness. In the first, the purpose of this thesis is the optimal design of a Class A chassis and body, based on general directives. Secondly, by performing static test depend on the weight and dynamic test caused by bumps, review the performance of chassis and body that are designed. With this work and to achieve the relative safety of designed chassis and body, in fact, the plan will be certify. It is important that before performing dynamic test, to have dynamic characteristics of Class A vehicle, modal analysis be done. Providing Chassis designed have good performance in static and dynamic tests, the rollover as an important road accidents will be simulated and the performance of the body under this simulation, will be surveyed. The remarkable thing about the design and optimization of the class A vehicle chassis and body is the amount of weight. In fact, in every steps of design and optimization, vehicle weight should be considered as the first and most important product system requirements. After the designed class A vehicle chassis and body according to standards, methods and models, the dynamic analysis was done. In the first analysis, chassis and body is not able to pass the tests. After the optimization of class A vehicle chassis and body, this work was done again. With increasing the thickness and removing sharp points as an Optimization methods, class a vehicle passed all dynamic tests successfully.In the last part of the thesis, rollover test simulated and this test for Modified model was done successfully.Sine half- pulse, simple step and simple pit was used for dynamic tests stimulation. Method that used for simulation of class A vehicle rollover test is FMVSS216 American standard.For Modal analysis, dynamic stresses caused by external loaded and simulation of rollover test designed class A vehicle chassis and body, Abaqus finite element software is used. This software using static and dynamic solvers. The solver used in this thesis, is dynamic method. For Kinetic analysis and reach to created forces by external loaded to the suspension attachment points to chassis and body Adams software is used. It should be noted that to achieve correct results in Abaqus software, mesh sensitivity and energy balance in all analyzes have been considered, although detail is ignored in the thesis. Key Words:Class A Vehicle, Chassis and Body Design, Dynamic Analysis, Modal Analysis, Rollover Test.