Polarization imaging techniques have been extensively employed in biomedical studies and clinical applications. As a comprehensive polarization representation, the Mueller matrix (MM) can provide abundant polarization-related information of biomedical samples. For quantitative information acquisition, groups of polarization basic parameters (PBPs) have been obtained through MM analysis and demonstrated as effective structural characterization tools of tissue samples. Recently, MM polarimetric endoscopy has shown great clinical diagnostic potential. For in-vivo polarimetry such as gastrointestinal MM endoscopy of human internal organ cavities, the complicated undulating tissue surface geometry delivers an inescapable occurrence of oblique incidence, which induces a prominent aberration to backscattering tissue polarimetry. Thus, quantitatively analyzing and reducing the polarimetric aberration induced by oblique incidence are crucial for in-vivo precision MM endoscopy. In this study, we quantitatively analyze the polarimetric aberration induced by tissue surface geometry on PBPs. A correlation heatmap is obtained as applicable criteria to select appropriate incident angle for different PBPs. Based on the analyzing results, we propose two aberration correction strategies of parameter selection and azimuth rotation, which are suitable for tissue samples with randomly and well-aligned fiber textures, respectively. Both strategies are demonstrated to be effective in the ex-vivo human gastric muscularis tissue experiment. The findings presented in this study can be useful to provide accurate polarization imaging results, widely applied on in-vivo polarimetric endoscopy for tissues with complicated surface topography.