The 72-hour post-earthquake rescue period have been a matter of priority in recent major earthquakes. The communication and network environments at the earthquake site are extremely complicated, so the conventional network access mode has difficulty guaranteeing real-time data and communication transmission from the site to the rear command center. In this study, based on the post-disaster relief work and damage caused by several destructive earthquakes in recent years, and the Wenchuan and Yushu earthquakes in particular, we analyzed several key emergency communication technologies for application to earthquake rescue sites and make recommendations on how to ensure effective communication at earthquake sites. We also studied the emergency communication system with respect to information flow at the rescue site, the emergency communication network, and the command center.