Air route utilization rate characterizes the usage of the airway in the airspace, which would make the use of the air space resources more reasonable and efficient. In order to calculate the air route utilization rate more accurately, the calculation method based on the multidimensional space was proposed by constructing the abstract multiple dimension spaces. A breakthrough had been made in considering the correlation factors of time and space, which leaded to the air route time-space utilization rate calculation model from the perspectives of time, air route and flight level. The air route utilization rate calculation model was introduced from the views of time, space and capacity based on the combination of air route time-space utilization rate and air route capacity utilization rate. Finally, the air route utilization rate of four air routes in a certain area control airspace was calculated through the example.