Handling and stabilities is important for steer by wire (SBW) system. Firstly, a platform for SBW handling and stabilities analysis and parameter optimization with friendly graphic user interface (GUI) is built based on Matlab GUI technology. Secondly, three degree of freedom handling and stabilities model with steering angle as input is built and system stability is analyzed based on Routh-Hurwitz stability and poles methods. Then simulations are carried out to show effects of some vehicle parameters on handling and stabilities. Finally, the handling and stabilities sensitive parameters are optimized using genetic algorithm method to improve step responses and handling and stabilities.