As one of the important indicators to measure the construction level of urban public development space, visible green index is extremely important to guide the construction of urban road greening landscape. This paper takes typical roads in the old town of Nanjing as the research subject, using methods of street view data capture and Matlab automatic identification and on-site investigation to calculate the visible green index. Then, the paper analyzes the factors that affect the visible green index, and proposes optimization suggestions for the current situation of road greening in the old town of Nanjing, and also provides reference for future landscape optimization construction.