During the oil well cementing, the cement shrinkage can lead to the formation of micro-annuli in the downhole annular space, resulting in issues such as gas channeling and fluid invasion. These issues which can compromise the integrity of the cement sheath. The addition of expansion agents can mitigate cement shrinkage. Therefore, evaluating the shrinkage/expansion behavior and gas migration resistance of cement systems with different expansion is critical for ensuring wellbore integrity. This study employed a multi-functional experimental apparatus for testing both the expansion/shrinkage characteristics and mechanical properties of cement during the setting. The setup also evaluates the gas leakage prevention performance of cement by gas channeling modules. An experimental investigation was conducted on cement slurries incorporating two different mechanisms expansion agents, B10 and QJ-625.The results indicate that the B10 expansion agent does not significantly alter the cement pore pressure development. However, a higher B10 concentration leads to more pronounced cement expansion and, consequently, superior gas channeling resistance after hardening. In contrast, the QJ-625 agent effectively inhibits cement shrinkage, with its effectiveness and resulting gas channeling resistance also improving with increasing concentration. Furthermore, the expansion effect of the QJ-625 manifests earlier in the cement setting compared to the B10. Additionally, QJ-625 has a more substantial impact on the mechanical properties of the cement sheath than B10. These observed differences in performance are attributed to their distinct mechanisms.