With an ever-increasing interests and demands in Near-Space , more and more researchers have put their attentions on this field, leading to an emerging needs for modeling the 20~100km altitude space especially for broadband communications. Among the lots of works, Media Access Control (MAC) undoubtedly has chief importance and urgency with which communicating objects or nodes can effectively access to Near-Space. However, previous MAC designs mainly focus their attentions on service differentiation by application purposes without considering nodal mobility. In fact, access control for nodes with different mobility levels has significantly influences to MAC performance and is complex and difficult to be implemented together with present MAC protocols. In this paper, we first presented a location method for Near-Space vehicles such as airships and unmanned planes and then modeled the mobile networks infrastructure with mobility considered. For determining the vehicles joining/leaving events locally, we quantify the communication range with Received Signal Strength Indicator (RSSI) aid. Then, for better managing the nodes access to the Near-Space with aforementioned works, we designed a TDMA based reservation MAC protocol to guarantee the service delay and networks coverage with best efforts. Simulation results showed that our proposed model better fit for Near-Space mobile communication environments and presented a lower delay and higher coverage regarding to different mobility levels.