Utilizing the 2012-2018 China Migrants Dynamic Survey data,a quasi-natural experiment was conduc-ted based on the construction of civilized cities to evaluate the impact and its underlying mechanisms of such construction on the self-employment of rural migrant workers.The studv found that the construction of civilized cities reduced the likelihood of rural migrants engaging in self-employment,and this effect did not exhibit spillover effects across regions.Specifically,the con-struction of civilized cities led to rural migrants actively choosing to abandon self-employment and shift towards formal employ-ment.The mechanism analysis revealed that the construction of civilized cities primarily reduced the probability of rural mi-grants'self-employment by increasing employment opportuni-ties,enhancing employability,and reducing employment dis-crimination.The heterogeneity analysis indicated that the con-struction of civilized cities prompted a greater shift from self-employment to formal employment among rural migrants with higher education levels who possessed greater capabilities,those from smaller households who were more inclined to accumulate social capital,and the new generation of rural migrants who were more willing to integrate into urban life.