Abstract: In this paper, a theoretical model is developed to evaluate the data transmission performance of RLNC-based Epidemic routing in DTNs. This model can trace the data transmission process under transmission bandwidth limitation and provides an insight about the characters of RLNC-based data transmission in DTNs. The data transmission delay of RLNC-based routing protocol is compared with that of conventional routing protocol. The results demonstrate the significant performance improvement for data transmission in DTNs brought by RLNC. The proposed model provides a general tool for performance evaluation and useful guidelines for designing RLNC based routing protocols in DTNs.