The invention discloses an RGB-D video based robot target recognition and localization method and system. The target category is determined and accurate spatial position localization is acquired in a scene through the steps of target candidate extraction, recognition, time sequence consistency based confidence estimation, target segmentation optimization, position estimation and the like. In the invention, depth information of the scene is utilized, the spatial level perception ability of a recognition and localization algorithm is enhanced, the identity and the relevance of a target in a long time sequence target recognition and localization task are ensured while the video processing efficiency is improved through adopting key frame based long-short time time-space consistency constraints. In the localization process, collaborative target localization in a multi-information modal is realized through accurately segmenting the target in a planar space and evaluating the position consistency of the same target in a depth information space. The RGB-D video based robot target recognition and localization method and system are small in calculation amount, good in real-time performance and high in recognition and localization accuracy, and can be applied to robot tasks based on online visual information parsing and understanding technologies.