Abstract: Facility agriculture realizes efficient annualized crop production by constructing a relatively closed and adjustable production environment, but its long-term high water and fertilizer inputs coexist with restricted washing conditions, which easily induces secondary soil salinization and has become a prominent problem restricting the sustainable development of facility agriculture. Based on systematically sorting out the current situation of soil salinization in China's facility agriculture, the paper comprehensively analyzed the synergistic mechanism of salinity accumulation by facility environmental conditions, irrigation and fertilization methods, and cultivation and management measures, starting from the source of water and salt and the migration process. The limited rainfall washing, high evapotranspiration intensity and long-term over-fertilization in the facility were the dominant factors for the continuous salt input and surface enrichment, while the destruction of the tillage structure and drainage obstruction further aggravated the upward migration and retention of salts. The mechanism and applicability of physical, chemical, biological and engineering measures under facility conditions were comprehensively evaluated as well. It is proposed that the prevention and control of secondary salinization in facility soils should be shifted from a single remediation measure to a front-loaded prevention and control mode centered on the control of water and salt processes, and construct a "salt monitoring - process diagnosis - comprehensive control" system. This system could provide theoretical basis for the long-term safe utilization of soil resources in facility agriculture.