Carbon footprint has become an effective method for assessing carbon emission, aiming at measuring the influence of atmosphere environment and climate change caused by human activities across the whole life cycle of a product or an activity. With rapid urbanization, residents in cities are playing increasingly important roles in the alteration of environment. Meanwhile, consumption is one of the remarkable drivers of environmental pollution in city areas. With the perception that unsustainable consumption patterns are the major cause of the continued deterioration of the global environment, environmental concerns move to household sectors and related lifecycle activities. Food is the most important consumable of daily household life. The carbon footprint of food shows the carbon emission of the food provisions for the whole city and the contributions to the climate change. Based on the theory and model of carbon footprint, and using the life cycle analysis (LCA), we calculate and analyze the carbon footprint of food consumption according to the reality of Beijing city and the food supply plan. The result shows that the total carbon footprint of food consumption is 4.768×10⁶t, about 6% of the total carbon footprint of Beijing, corresponding to 310.0kg/cap, and accounting for 23.3% of the total emission of household consumption, which is only 5.96% of the total carbon dioxide emission in Beijing. This reflects the limited impact of food consumption on the environment, carbon emission, and climate change. If Beijing wants to achieve a goal of carbon reduction of more than 6%, it is not sufficient to take measures in the field of food consumption alone. The most important part of food consumption carbon footprint is from grain, and the second part is from fruits and vegetables. These two parts account for more than 65% of carbon footprint of food consumption. The most important process of food consumption carbon emission is from reprocessing and cooking of foods, which consume most of household energy, and result in almost 60% of the total carbon emission. One important reason for this phenomenon is that this process directly refers to energy using which serves as the most important action leading to carbon emission. The second important process is usage of chemical fertilizers and pesticides, which shares 23.23% of total food carbon footprint. Production and transportation are also important processes, which account for 8.35% and 6.98% of the total food consumption carbon footprint, respectively. Reduction of carbon emission in food reprocessing and cooking is the available process to reduce carbon emission from food consumption. And if we don't use chemical fertilizers and pesticides and promote ecological agriculture (or organic agriculture) in our food production or improve the used-rate, we can reduce 1.351×10⁶t CO₂ every year in Beijing, that is 87.84 kg CO₂ per capita per year. It is quite an efficient way to reduce carbon emission of Beijing city. We also compared the results of our improved method with the national average datum, and found that there are some reasonable differences attributed to the calculation method and parameters such as cropland area. The results also show that other parts of Beijing residents' consumption such as transportation, daily commodities and energy use have great contributions to carbon footprint. So further research need to be carried out on residents' other kinds of consumption in households to make an overview of total carbon footprint of residents.