In MANET, the scheme for maintaining an inter-zone route in ZRP makes ZRP take more lost packets and more route re-discovering times; the former makes ZRP take lower delivery ratio of data packets, which makes ZRP take less reliability; the latter makes ZRP take more transmission delay and more routing overheads. Aiming at the problem above, a MANET-based reliable zone routing protocol (MRZRP) was proposed. In MRZRP, each node saved multiple backup routes from the node to each intra-zone node by maintaining an directed acyclic graph based on an intra-zone topology, and an inter-zone route was repaired by using backup segment routes as much as possible. The simulation results show that MRZRP improves delivery ratio of data packets, which shows that MRZRP improves the protocol reliability, and MRZRP also reduces the transmission delay and routing overheads.