The opportunistic network is intermittent. It is based on the principle to carry, store, and forward the messages for routing from source to destination. It is very prominent in recent years as it provides an alternative to conventional networks. But, it has low-delivery probability and high latency. In the proposed model, the performance of the system can be increased by the use of the priority-based buffer management technique (PBMT) with a threshold. It not only forwards the message according to priority but also controlled the random dropping of the message. Various simulations are analyzed by comparing the proposed mechanism with the other two benchmark buffer mechanisms such as first in first out (FIFO) and random by using real-time mobility data-trace. PBMT with threshold provides higher delivery probability 7.85%, 16.29% with the TTL, 2.98%, 4.35% with the buffer size, and 6.10%, 14.41% with the message generation interval as compared to random and FIFO, respectively. It also provides lower average latency 4.05%, 16.81% with the TTL, 4.54%, 2.34% with the buffer size as compared to random and FIFO, respectively. Results of these simulations confirm that the PBMT with threshold shows a significant improvement in the performance of opportunistic networks (OppNets).