As critical areas in the response to global climate change,there is a great need to research household carbon emissions in megalopolises,such as those in China. Across Xi'an households there is a deep relationship between key impact factors and low levels of economic development. Here we estimated characteristic and impact factors of residential carbon emissions for 915 households in Xi'an using survey data from micro-family activities in 2015. We found that households produce 12 111.87kg CO_2 every year. The ratio of family living to transportation is 4∶1. Electricity accounts for 41% of residential energy consumption. The car is the driving factor of carbon emissions in family transportation. The highest income group showed a strong willingness to buy green products and improve environmental quality. In summer,the temperature setting of airconditioners is 23℃,lower than the national recommended standard. After housing spaces increase from 60m~2 to 80m~2,carbon emissions rise considerably. As the distance between community and shopping malls becomes longer,more households choose car travel. It is not only the pursuit of modern life,but also once a car has been acquired,people become dependent on it for virtually all journey purposes. Migrant families choose to improve their living environment and at the same time consume more resources and increase their carbon emissions. Our society is still emphasizing meet peoples basic needsin Xi'an,so the city cannot achieve abstemious society completely. These results will guide the effective pathway to reducing residential carbon emissions and help design policies to develop low-carbon lifestyles in Chinas megacities.