A bottom-seated oscillating water column (OWC) device with a front lip-wall which is allowed to oscillate in a pitching mode is explored under the framework of potential flow theory. By utilizing the matched eigenfunction method and employing the continuity conditions along the adjacent common interfaces, the theoretical model can be transformed into a set of linear equations. Some potential influential factors, including the linear density (rho_s) and draft (d) of the front lip-wall, the chamber breadth (b) and the imposed angle spring stiffness (K), are examined to study their effects on the wave power extraction performance. The results show that the inclusion of a pitching front lip-wall can effectively expand the frequency bandwidth of high-efficiency, especially under the geometry condition of a relatively larger front lip-wall draft and larger chamber breath. In addition, the examination of different spring stiffness K demonstrates that it is more beneficial for the energy extraction when K is designed as a relatively lower value or even set to 0.