Based on photograph,ichnography,interviews,questionnaire survey and statistical analysis methods,this paper discusses the evolution and mechanisms of vernacular dwellings in agricultural villages in the past 30 years by selecting three villages with different natural-human characteristics in Hebei,Shandong and Henan provinces as the detailed case studies. Generally speaking,the outer appearances of vernacular dwellings such as the house facade,building materials and technologies have been modernized and de-localized generation after generation.The inner patterns of vernacular dwellings has been specialized and segregated by age,activity and gender gradually,at the same time,the living space has been strengthened even over-developed continually;the agricultural space was regenerated and reorganized at first and then weakened owing to the increase of peasants' non-agricultural job opportunities and incomes;the kitchen,bathroom and granary have been gradually moved from yard to main house.The above-mentioned evolution processes can be divided into four periods in detail. As far as the relationship between generations of vernacular dwellings and household socio-economic characteristics is concerned,demographic characteristics of househols are the important driving force for the difference of generations,which is correlated with household income,and the migration of household members has obvious effects on it also. Some special traits of vernacular dwellings evolution in the case villages are produced by traditional culture,rural institution of property and distribution,and the urbanization process.The vitality of traditional culture remains so strong that many of its symbols are represented vastly by the modern materials in current vernacular dwellings.The collectively-owned but equally distributed farmland makes the household population and household life-cycle become the determinants for household income disparities and indirectly leads to the difference of vernacular dwellings in agricultural villages.The amphibious migration of rural labor promotes the diffusion of industrialized artifacts,technology and life style in agricultural villages,which,however,results in the lavish construction of vernacular dwellings at the same time.