Abstract: Pathological detonation is a kind of non-ideal detonation that chemical reaction heat release cannot be fully used to support the propagation of detonation wave. It is common in the practical processes, and the study on propagation stability of the detonation is of great significance. In this study, the pathological detonation process is realized by using a single-step reaction with a reduced molar number. The oscillation instability process of one-dimensional pathological detonation wave propagation is numerically simulated by using one-dimensional reactive Euler equation and high-resolution numerical scheme. The effects of piston-driven speed and activation energy on the stability of pathological detonation wave are systematically investigated, and the relationship between the stability of detonation wave and the reaction zone structure is analyzed. The results show that the pathological detonation is more unstable than the ideal detonation wave under the same reaction exothermic conditions. The increase of piston-driven speed is beneficial to the stability of the pathological detonation wave, while the increase of activation energy can lead to the instability of the pathological detonation wave. The high-frequency and low-amplitude oscillation of overdriven pathological detonation has little change in the structure of the reaction zone; the low-frequency and low-amplitude oscillation of detonation wave under the condition of strong solution is caused by the alternation of two configurations of strong solution in the reaction zone. The low-frequency and high-amplitude oscillation characteristics of overdriven pathological detonation are characterized by the alternating occurrence of reaction zone structures such as weak solution, strong solution and overdriven solution.