To manage State Safety Program (SSP) in a more integrative and proactive manner, an aviation safety authority of the state shall detect and assess the risk of emerging or hidden safety hazards before they provoke accidents or incidents(<xref ref-type="bibr" rid="B7">ICAO, 2018</xref>). In case of South Korea, safety risk assessment is conducted by calculating the likelihood and severity of the hazard following ICAO’s safety management manual. It is reasonable to extract the safety risk likelihood by calculating the number of occurrence caused by the hazard. However, it is ambiguous to assess the safety risk severity defined as the extent of harm that might be expected to occur as a consequence of the identified hazard. In this paper, a safety risk assessment method which quantitatively calculates the risk of hazard using aviation safety data(i.e. aviation safety mandatory report, etc.) is proposed. By utilizing the proposed method, the existing process that safety risk is being subjectively assessed by safety inspectors can be supplemented. So that essential aviation safety policy decision making can be accomplished by the accurate result of safety risk assessment.