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In the fields of agricultural production management and climate change research, it has been well recognized that monitoring large-scale plant phenology with satellite-based remote sensing is of great significance to reveal the process of the interaction of biology and nature environment. In the activities of validation on remotely sensed phenology information, near-surface digital cameras are often employed as main data sources. However, more efforts were focused on the scale difference between ground and remotely sensed data, and rarely on the difference of sensors viewing zenith, i.e., the satellites mainly adopted the near- nadir observation while cameras were mostly inclined arrangement. In order to systematically assess the effects of camera observation angles on the satellite phenological verification results, vertical (PhotoNet) and inclined (PhenoCam) camera observations were acquired at the similar latitude for the same vegetation type, then we compared them with phenological parameters extracted from Sentinel-2 data. For sixteen locations we compared greenness chromatic coordinate (GCC) series derived from digital cameras and Sentinel-2. A double hyperbolic tangent model was fitted for each series. The threshold method was applied to the annual complete modelled data, and the curvature extremum method was used for incomplete data to estimate onset of greenup, maturity of the green canopy, peak of season, end of greenness and dormancy of the green vegetation (OG/MG/PS90/EG/DG). The results showed that the viewing zenith of cameras is one of the uncertain sources to validate phenology information from satellite imagery. In most cases, the vertically observed camera showed better agreement with the phenological parameters extracted by satellite-based method, with an average bias of 9 days, while a larger bias of 19 days was observed for inclined camera observation. Therefore, the two camera observation methods result in the verification deviations of up to 10 days on average. However, the deviations might be vegetation type and growth stage dependently. It was found that the bias of vertical observation was significantly higher than that of inclined observation during the end to dormant period for maize. The different result of the vertical and inclined camera on the similar vegetation can be partly explained from the directional reflection characteristics of vegetation canopy and the difference of target components (e.g., different fraction of soil and vegetation, photosynthetic and non-photosynthetic components of vegetation) within the camera field of view. Our results demonstrate that the viewing zenith angle of the near-surface cameras is an important factor in validation of satellite phenological parameters. In addition, the analysis found that the uncertainty of verification results caused by phenological period extraction method, illumination and satellite observation geometry is limited, which is not the main factor affecting the verification of satellite phenology parameters. As a result, it is suggested that to provide more reliable verification data for satellite remote sensing monitoring, the verification error introduced by angle effect should be fully considered while near surface cameras are deployed in the field.