Abstract: An important position as a risk factor of air parameters in the lightning risk assessment calculation，the accuracy of the evaluation results directly affects the accuracy of risk assessment results，location factor given current lightning risk assessment standard of the typical experience of value. The randomness of the value leads to the lack of pertinence of the calculation result and leads to great error. To solve the above problems，the calculation method of quantitative location factors put forward，location factors is the ratio of the thunderstrike equivalent area calculated as the buildings around it are taken into consideration to that of the thunderstrike equivalent area as the buildings are isolated. Finally，a common residential district is calculated，and the deficiency of the current calculation standard is analyzed. The rationality and validity of the quantitative calculation method are verified.

Key words: risk assessment, location factor, quantitative calculation