Topological zero-line modes (ZLMs) based on valley Hall effect induced by inversion symmetry breaking have attracted numerous attention in designing topological quantum devices. Compared with the toy model in monolayer graphene with staggered sublattice potentials, ZLMs in bilayer graphene are more accessible in experiments. However, it is still experimentally challenging to design the fine-tuned electric gates to realize ZLMs, and the introduction of electrodes also makes it difficult to further reduce the device size. In this work, we demonstrate the emergence of ZLMs in bilayer graphene from layer-reversing in-plane electric fields, which are induced by chemical dopants. Our proposal provides an experimentally feasible and new route to realize electrodeless ZLMs in graphene systems.