With harmonic resonant vibration synthesis, resonant-type piezoelectric impact motors show a great improvement of power output capability against traditional piezoelectric impact motors. In this paper, a resonant-type inertia drive linear motor with piezoelectric asymmetric tuning-fork actuator is proposed. Structural design and working principle of the motor is descripted. A simplified mechanical model of the piezoelectric asymmetric tuning-fork actuator is established to investigate the frequency trends of the anti-phase and in-phase bending vibration modes of the structure. With FEA simulation, modal analysis of the structure is used to determine the optimal sizes of the components, resulting 1:2 frequency ratio of the two bending vibration modes. A prototype motor is manufactured to test the characteristics of the two vibration modes and their frequency trends.