The purpose of this study is to investigate the unsafe conditions of pedestrian crossings at signalized intersections under the mixed traffic environment in Changsha, China. For this purpose, based really pedestrian-related crash data of Changsha city and visualized crash geographic information, six typical urban signalized intersections were selected. The peak and off-peak surveillance videos of six signalized intersections were collected via field surveys, 1,070 conflicts were extracted through using professional trajectory tracking software Traker to track pedestrian and vehicle trajectories. PSMT (Pedestrian Safety Margin Time) was used as an indicator to identify the severity of conflicts, and manually recorded the characteristics of pedestrian crossing behavior, vehicles and roads during the conflict. An Ordered Probit model was established to analyze the risk factors that led to different severities of the conflict between pedestrians and vehicles. The model outcome indicates a significant relationship between the severity level and characteristics of pedestrian behavior, vehicles and conflict. Moreover, it was identified that, in addition to the above characteristics, roadway characteristics significantly influenced likelihood of severe pedestrian-vehicle conflict. Finally, these factors are discussed, and suggestions for improving the pedestrian traffic environment are proposed from different perspectives.