The application of fractal theory in research on the urban morphology is initiated from research on traffic network. A lot of case researches made by scholars at home and abroad have been shown that the fractal feature and fractal dimension would become a relatively ideal and useful measured indicator to remark the form and property of traffic network in a city and explain the process and dynamics of developing and evolving of the network. This paper has taken the traffic network in Shanghai Metropolis as a study case, by using the fractal dimension of the traffic network measured and calculated in Shanghai and its some districts, the spatial changes of the fractal feature have been researched. By comparing the fractal dimension in deferent periods measured and estimated in the city and districts, the temporal evolution of the fractal feature have been investigated. The results show that the value of 1.7 of fractal dimension of a traffic and road network in a lot of metropolises, big and medium size cities and some urbanized areas has a universality’s meaning, it will be an appropriate indicator for evaluating and judging the form, function, structure and perfectiveness of the traffic network. As to the changes of fractal dimension in the spatial field, the fractal feature of the traffic network in the inner city of Shanghai is more complicated than that in the outer city, and the fractal dimension is gradually decreased from the inner to the outer city along the main developing axes of the city. In the temporal field, the fractal feature and complexity of the traffic network in the recent period is higher than that in the earlier, the form strength of the network has been optimized gradually. This general evolving tendency is coincided with the developing processes of the city. It is believed that the fractal dimension and its evolution will become a most useful indicator for describing and explaining the morphological process of the city explicitly together with other useful city’s indicators.