To solve the problem that the current routing protocols in MANET cannot be used in AANET (Aeronautical Ad Hoc Networks), we propose the Hierarchical Space routing protocol (HSRP). Section 1 of the full paper gives five definitions that we have come up to find useful in describing HSRP protocol. Section 2 uses the above-mentioned five definitions to design the HSRP protocol; the HSRP protocol has the ability to dynamically change the update frequency of HELLO beacon and adjust the radius of routing space in according with the air traffic; section 2 also gives the architecture of HSRP protocol and the procedure for implementing the HSRP algorithm. Section 3 does three experiments to test the HSRP protocol. The experimental results, shown in Fig.1, Fig.2 and Fig.3 of section 2, indicate preliminarily that the HSRP protocol compared with ZRP protocol can adapt better to the impact of air vehicles density change on routing protocol and has higher delivery ratio, lower routing control overhead and lower average end-to-end delay, in addition, the HSRP is practical and effective in AANET.