Synergistic evolution theory of crop germplasm resources and cultural environments is about the interference, interaction, and interpromotion between each other. On one hand, culturing different crops in a specific environment will lead to the formation of corresponding dietary traditions and cultural environments, on the other hand; dietary traditions and cultural environments will in turn have a profound influence on the formation of crop germplasm resources and might even lead their evolution. The genetic basis of this theory is that after the natural hybridization or mutations of the crops occurred during the processes of their dissemination and improvements, they are targeted and fixed under the artificial selection of the specific cultural environments, the frequency of the recombinant or mutant genes continues to accumulate and increase in the population, and finally form new crop and their germplasm resources adapted to the specific cultural environments. Modern crop breeding is also guided by this theory to a certain degree, which greatly promoted the evolution processes of crops and their germplasm resources. Taking the Customary System of Chinese traditional dietary culture as an example, this paper investigated the impact of dietary tradition on the evolution of crop germplasm resources from four aspects: waxy germplasm, steaming preference, rich varieties of vegetables and fruits, and use of whole-plant material. In view of the protection and utilization of crop germplasm resources in the future, suggestions were proposed, including paying attention to farmers’ rights and original habitats of crops, and following the basic law of “if there were character differences and genetic mutations, then select” to accelerating the landrace, crop wild relatives preservation and utilization, genomics research, and crop improvement as well as their positive evolution.