Starting from the status of citizenization of land-losing farmers, problems in the citizenization are analyzed, such as the difficulty in land-losing farmers’ economic life after turning into citizens, employment difficulties of land-losing farmers after living in the city, and the prominent problems in social security of land-losing farmers. Causations for the citizenization problems of land-losing farmers are analyzed. Firstly, institutionalized rejection is the root of the obstacle in citizenization of land-losing farmers. Secondly, exclusion from social security system is a fundamental reason. Thirdly, exclusion of land-losing farmers from both urban citizens and themselves is the subjective factor. Fourthly, exclusion of land-losing farmers from urban employment is the objective factor. Based on these, countermeasures are put forward: formulating a reasonable price of land transfer; establishing a reasonable land compensation and benefit-sharing mechanism; setting up a multi-level social security system for land-losing farmers; increasing the human capital investment in land-losing farmers to enhance their employment status; and improving the cultural quality of land-losing farmers to realize the change in lifestyle.