A problem of research on overlay network is lack of testing platform. Recent research has shown that one can use Distributed Hash Tables (DHTs) to build scalable, robust and efficient applications. However, large-scale distributed systems are hard to deploy, nor are DHTs . OpenDHT is a publicly accessible DHT service. In contrast to the usual DHT model, clients of OpenDHT can issue put and get operations to any DHT node, which processes the operations on their behalf. This paper introduces OpenDHT and concentrates on how to do the network testing based on OpenDHT. The testing about resource location is also expounded .