Abstract: It is believed that most of parameters influencing the interarrival time of landing are random variables, so the setting up of a runway landing capacity model must be based on probability theory. From the viewpoint of a controller, a probability model of runway landing capacitywas proposed. In this model, the effects of approach speed, position uncertainty, wind speed, runway occupation time and traffic mix on runway landing capacitywere sufficiently considered and actual statistic data were its basis. In addition, a calculation example was given. The calculated result shows that runway occupation time and separation time standard influence greatly runway landing capacity and the effects of the other parameters are relatively small.