The invention discloses an intelligent tree trunk white painting robot and belongs to the related fields of urban and garden greening equipment. The intelligent tree trunk white painting robot comprises a machine frame system, a robot traveling system, a lime slurry supply system, an automatic white painting execution system and a real-time detection system. Adopting a spray painting mode for white painting of tree trunks, the robot can automatically walk along a side pavement and quickly and efficiently spray lime solution onto trees along the side pavement. In a real-time detection system, a digital compass, a laser sensor and a vision system are adopted to realize the semi-automatic searching of tree trunks and tree trunk automatic positioning, an ultrasonic transducer is adopted to realize automatic obstacle avoidance, and the whole-process real-time monitoring with a personal computer (PC) and a programmable logic controller (PLC) is realized. When the intelligent tree trunk white painting robot is used, coating is saved and the painting effect is optimized; and the robot automatically performs white painting of trees along the side pavement, the working efficiency is improved, labor force is saved, and the goals of intelligent control and green environmental sanitation are fulfilled.