After a disaster occurs, effective communication between the people and the institutions of disaster or emergency management is vital. Device to device (D2D) discovery and communication provides communication services in such difficult situations without the requirement of network infrastructure and by reducing call traffic in cellular communication networks. Considering the fact that almost everyone uses a smart mobile device (UE-User Equipment), the D2D communication method seems the most suitable solution for a post-disaster situation. In particular, this method plays important role in fifth generation 5G communication networks. The device discovery or UE discovery is fundamental strategy in D2D communication. In this study, a Throughput-based Discovery Algorithm (TDA) is proposed to find D2D peers among devices on Public Security Network (PSN) in a post-disaster situation. A sample scenario was created to test the performance of the proposed TDA, and the TDA was compared to some discovery algorithms, such as Shortest Distance Algorithm (SDA), Maximum SINR with No limit on the distance of discovery Algorithm (MSNA), and Maximum SINR with Limit on the distance of discovery Algorithm (MSLA). In terms of the outage SINR and average pair SINR metrics, the proposed TDA showed better performance than the other discovery (MSNA, SDA, and MSLA) algorithms for D2D discovery in the disaster area.