In this paper, a specific directed-graph framework of flock interaction and collective dynamics of flapping-wing swarm robots are presented. The flock of flapping-wing robots is suitable for long distance tasks. A visual interaction topology network of flapping-wing robots under distributed control is considered for low battery cost. The network consists of a directed topology structure to describe an information delivery mechanism of a flapping-wing robots flock equipped with visual sensors. It is assumed that bird flocks in nature have similar directed interaction topology structure. Furthermore, a collective dynamics model for bionic flapping-wing robots is raised, in which robots are Spontaneously organized into formation while avoid running into each other. In order to validate collective dynamics of flapping-wing robots under simulation environment, range-limited Delaunay division graph is utilized to fit the realistic visual interaction among swarm robots. Several numerical simulation results are provided to demonstrate the effect of the presented collective dynamics.