Abstract: Searching for files in popular unstructured P2P file-sharing systems contributes to much of internet traffic. While existing mechanisms can locate popular files easily, studies show they fail to find rare files exiting in the system. In fact the benefit users obtained from rare resources is not less than popular resources. So high searching hit for rare resources will dramatically improve the whole P2P networks practicability. This paper proposes a simple distributed mechanism-NLIR which makes it easy to find rare files as well as popular files. According to peers heterogeneity, it distributes rare files index replications uniformly into the networks. Even with constraint conditions that bandwidth and storage is limited, it can achieve high hit-rate for rare resources. Both analysis and simulations demonstrate it improves the performance of the system.