This paper presents the first-of-its-kind electrochemical seismic sensor where, a liquid proof mass (e.g., electrolyte solution) was used as the sensing element to translate environmental vibrations into active ion imbalances between electrodes, and therefore producing electrical current outputs. Theoretical analysis and numerical simulations were conducted to confirm the feasibility of the device concept and the proposed micro seismic sensor was fabricated by conventional MEMS technologies. Device characterization based on a vibration table recorded a linear relationship between applied velocities and output voltage amplitudes with a calculated sensitivity of 274 V/(m/s) (20–80 Hz). The performance of the proposed micro device was compared with a commercially available macro counterpart (MET2003), indicating strong correlations of these two types of devices in response to random vibrations while the proposed micro seismic sensor was capable of producing a lower power spectrum compared to MET2003. In summary, the electrochemical micro seismic sensor developed in this study is featured with mass fabrication capabilities due to MEMS technologies, comparable performance and lower power spectrum compared to conventional electrochemical seismometers. This newly developed micro sensor can be potentially used in the field of seismology, enabling the ground motion monitoring to locate earthquakes, volcanic eruptions, and other seismic sources.