The utility model relates to a drop hammer deflectometer. The drop hammer deflectometer comprises a bearing plate, a guide rod, a drop hammer and a data acquisition transmission device, wherein the data acquisition transmission device comprises a power source, a shell, a data acquisition unit, a CPU (Central Processing Unit) controller, a displayer and a connector, and data measured by the drop hammer deflectometer is transmitted to a host machine through the data acquisition transmission device, thus the purposes of improving test work efficiency and saving manpower and material resources are fulfilled; and therefore, the large-scale popularization of the drop hammer deflectometer is facilitated.