The result of food safety risk assessment is the scientific basis for formulating and revising the food safety standards, and exercising food safety supervision and administration. Therefore, the accuracy and reliability of the result of risk assessment will affect the decision making of food safety risk management. Risk assessment methods, statistic parameters, models and health-based guidance values are some of the most important parameters that affect the result of risk assessment. Meanwhile, there are some misunderstandings and incorrect use of these parameters. This paper discussed the choices and usage of these parameters in the risk assessmentof food chemicals.