Abstract: Taking the Renmin Viaduct in Guangzhou the first urban viaduct in Chinaas research object, this study has combined the theoretical research with empirical study. This research is to provide empirical evidence for the application of space syntax in Chinese urban traffic forecasting, to explore a better forecasting model to fit the actual traffic flow and to provide reference for the optimization of road network. Based on the normalized angular choice (NAchoice)an advanced algorithm of Space Syntax theorythe paper has discussed the case from three aspects : current traffic situation of Renmin South road, the effects viaduct demolition takes on Renmin road traffic flow and assessment of traffic evacuation ability within arterials in the scope. Conclusions can be obtained as follows: (1) Large traffic volume contributes to the frequent traffic jam in Renmin Road; (2) Removing elevated line will not necessarily make all the traffic flows on the viaduct stack up to Renmin Road, though slight increase of transportation in Renmin Road is possible; (3) Other main roads take limited effect on regulating and alleviating traffic pressure on Renmin Road. Therefore, Renmin Viaduct shouldnt be removed until roads are built to share the heavy traffic burden on Renmin Road; (4) NAchoice model has preferably fitted the collected traffic flow data, making it reasonable to apply space syntax on urban traffic simulation. This research also aims at exploring a contextual model which is able to evaluate and even instruct further traffic network design as well as the urban context preservation and extension.