The distribution characteristic of RTT (round-trip time) is an important part of Internet end-to-end behavior characteristics. People have made lots of studies of it, but many conclusions only adapt to the cases of small packet loss rate. We study the RTT characteristics on nearly 40 end-to-end paths in CSTNET and CERNET in China, and draw the following conclusions: (1) the distribution characteristics of RTT and loss rate are dependable; (2) when loss rate is small, RTT distribution is usually unimodal, but with the increase of loss rate, RTT distribution is no longer unimodal and it becomes more and more decentralized; (3) with the increase of loss rate, the occurring times of inherent RTT tend to decrease.