In this study，we used case-based situational approach and three-factor inter-experimental design to examine doctors’ attribution of responsibility to negative medical outcomes from three aspects：the size of the outcome event，the controllability of the outcome event，and the level of involvement. The results showed that the size of the events had a significant impact on the variables of responsibility，anger，criticism，verbal attacks and physical attacks，but had no effect on the variable of trustworthiness of the experts. The controllability of events had a significant impact on the variables of responsibility，anger，criticism，verbal attacks and physical attacks，but had no effect on the variable of trustworthiness of experts. The level of involvement had influence on variables of responsibility，anger，criticism，verbal attacks and trustworthiness of experts，but had no effect on the variable of physical attacks.