Micro-shell resonator gyroscope (MSRG), serving as angular velocity sensors, is utilized in aerospace navigation systems due to its high precision and reliability, playing a crucial role in ensuring accurate positioning and guidance. However, the charge accumulation effect within dielectric materials significantly limits the long-term internal stability of MSRG, thereby impacting its precision and reliability. In this paper, we focus on the of charge accumulation in MSRG without tuning electrodes. To gain a deeper understanding, a theoretical model of charge accumulation for MSRG is established based on stiffness variations. This model is employed to analyze the impact of charge accumulation on stiffness asymmetry, a critical factor influencing gyroscope performance. To validate our theoretical framework on charge accumulation, we conducted an experiment and successfully detected charge accumulation effect. Over a 140-min experiment, the charge accumulation effect is characterized by measuring and analyzing the frequency split and stiffness axis angle of the micro-shell resonator by a novel characterization method based on the frequency output under the self-precession mode. The experimental results indicate that the stiffness axis angle of the micro shell resonator is shifted by about 4° and the frequency split is changed by 75 mHz due to the charge accumulation effect. These measurements provided valuable insights into the dynamic behavior of MSRG and revealed the intricate interplay between charge accumulation and gyroscope performance. Our findings suggest potential pathways for mitigating the adverse effects of charge accumulation on gyroscope performance, which could lead to significant improvements in the long-term stability and precision of MSRG.