The flight test risk assessment is a vital part of flight test activity, and is a basic safeguard for flight test execution. To reduce the test risk, a method of flight test risk assessment is researched and developed, including test hazard identification, risk analysis, and the method of establishing risk mitigation and emergency measures. A risk assessment case is conducted based on the first flight of civil aircraft. Many kinds of hazards are indentified and their corresponding risk mitigations and emergency procedures are designed. The risk assessment results based on this method satisfy the basic requirement of flight test risk management.