A digitalization drop hammer instrument for lowvelocity impact testing was developed.The mathematical model of measurement and analysis of the instrument was established with friction and air resistance taken into account and the error estimation was completed.The instrument was mainly composed of a mechanical part and a data acquisition & processing part. The mechanical part included a linear guide,an electromagnet,a clamp and an impact hammer. The data acquisition & processing part included a hardware circuit,a LabVIEW data acquisition program and a MATLAB data processing program for calculating partial parameters using the fourthorder Runge-Kutta method.The relationships between any two impact variables such as velocity,acceleration,displacement,force,and energy were obtained and the digitalization description of the whole impact process was achieved,which could not be realized by traditional drop hammer impact testers.The impact properties of fiber/resin hybrid composites were investigated by this instrument,which fully showed the reliability,progressiveness and moneysaving of the instrument. This equipment provides reference for numerically analyzing the impact properties of different materials and structures.