Food production is considered as a major contributor for greenhouse gas (GHG) emissions. Unbalanced diet is regarded as a major driver to health problems. Dietary optimization presents challenges of supporting nutritional need and mitigating GHG emissions in China. In this paper, a hybrid approach of optimization model and life cycle analysis were introduced in order to obtain an environmental and healthy dietary patterns. Based on data sets of food survey and agricultural input-output, 15 types of food were incorporated with linking nutrient content and greenhouse gas emissions in the framework of life cycle analysis. The system boundary included the production of food and related materials (e.g., pesticide, fertilizers, and film). The developed approach was then demonstrated in dietary patterns of Guangdong Province, China. The target of the optimization model was minimizing greenhouse gas emissions. Residents’ dietary preference and national dietary guidelines were considered in the optimization model. The desired dietary patterns was thus obtained. The results indicated that dietary patterns of residents in Guangdong Province could be optimized in order to fulfill the goal of GHG mitigation.