Congestion has become one of the major social problems in many large cities including Beijing. While much research attention has been paid to the impacts of traffic congestion on individuals' stress and time pressure, not much research has been done on its effects on positive psychology such as the subjective well-being (SWB) of daily life. Based on the data from a one-day activity-travel dairy collected in Beijing, this paper contributes some empirical evidences on the impacts of traffic congestion on individuals' affective and cognitive SWB of both travel trips and its aim activities. The results of the structural equation model show that traffic congestion not only has negative impacts on travel experiences, but exerts strong negative effects on the activities following a congested trip. The negative impacts of congestion on SWB can be levitated or aggravated by various trip characteristics, such as transport modes, trip purposes, activity companionship, and activities conducted during the trip. Implications of findings from this research are that traffic congestion avoidance policies should not only focus on shortening travel time, but also need to consider the traveller's SWB in a specific trip.