The invention relates to equipment for preparing concentrated liquor by utilizing low pressure and low boiling point and a working method thereof. The equipment comprises a boiler unit, a flow storage unit, a cooling unit and a pressure reduction unit and is characterized in that a sampling unit is arranged on the side wall of the boiler unit and close to the bottom; a condensing unit is arranged on an upper cover of the boiler unit; a sampling cavity of the sampling unit penetrates through the top and bottom of a basal body; an equal pressure cavity penetrates from the front of the basal body and penetrates through the front and back of the sampling cavity; an airtight barrel of the flow storage unit is communicated with the outside by a first pipeline, a second pipeline, a third pipeline and a fourth pipeline; an output pipeline, a water outlet pipeline and a water inlet pipeline of the boiler unit are respectively connected with a second switch of the flow storage unit, an input end of the cooling unit and an output end of the cooling unit; a third switch of the flow storage unit is connected with an input end of the pressure reduction unit; and a first switch and a fourth switch of the flow storage unit are connected with the atmosphere. The concentration equipment disclosed by the invention has good reliability and high concentration efficiency.