The invention provides a high salinity wastewater energy-saving evaporative crystallization system and a technology thereof. The system comprises a wastewater preheater, a heating chamber, an evaporation chamber, a steam compressor, a vacuum system, a solid-liquid separation device, a circulating pump, a feed pump, and a condensate water pump. High salinity wastewater enters the heating chamber for preheating, enters the evaporation chamber for steam heating, and undergoes flash evaporation under vacuum and at low pressure; the evaporated steam enters the steam compressor for compression and warming, and the compressed steam enters the heating chamber again to heat the wastewater; condensate water is then used to preheat the high salinity wastewater, and the heat taken away by the evaporated water is further recovered. The heating chamber and the evaporation chamber of the invention adopt an integrated structure, the wastewater directly enters the evaporation chamber for flash evaporation after being heated, the concentrated liquor enters the circulating pump through the bottom of the evaporation chamber to be circulated to the heating chamber for continuous heating, and the liquidforms an inner circulation until the crystallization starts. The invention has the advantages of energy conservation and high efficiency, small equipment occupation, less equipment investment, etc.,and zero discharge of wastewater is finally achieved.