The invention discloses a spatial DTN link available bandwidth estimation method and system based on a queuing model. The method is characterized in that probe bundles are sent on a spatial DTN link to collect time delay information; transmission processes and delivery time delays of the bundles are analyzed, an M/D/1 queuing model is established for an arrival and departure process of the bundles through knowledge of the queuing theory, and a relation between a staying time of the bundles and network traffic is derived to estimate a spatial DTN link available bandwidth; and finally, a simulation experiment is carried out on an MATLAB platform through the Monte Carlo method. Experiment results show that through the algorithm provided by the invention, the spatial DTN link available bandwidth can be more accurately estimated, so that data guidance can be provided for QoS service.