To analyze the cause of driving accidents，firstly，this paper describes the main factors of driving accidents，like physical and psychological factors of drivers and environmental factors，combining with cognitive psychology. Based on these factors above，we make a brief analysis of them which impact on safe driving accidentmechanisms. Then we utilize the factors of driving accidents to design experiments and collect data. Based on statistical principles，we describe driving accidents as dependent variables and subjective factors and road conditionsobjective factors as independent variables. All of the process above are accomplished by utilizing of SPSS software.We analyze the effect of driver’s subjective factors and traffic environmental factors which impact on the probabilityof safe driving，contribution degree and correlations of road accidents. The results demonstrate that for the drivers，the influence of psychological factors and physiological factors are bigger than environmental ones，which means thatsubjective in driving accidents are much more influential than the objective factors.