The governance of traffic congestion is an important issue of current traffic management. In order to analyze the difference of the choice of travel modes in forced travel and elastic travel in Nanjing residents, this paper makes elastic analysis and parameter estimation for various types of transportation such as public transportation. Found that the travel mode choice behavior compared with forced travel mode and elastic travel patterns has obvious different. The forced travel mode will have more influence on the choice of monthly income, travel distance and daily travel time. The travel distance, daily travel time and the time period of the trip are more significant in the elastic travel mode.