The invention discloses a vaporization system for preheating stock solution, comprising a stock solution groove, a tubular heater, a dissolution device and an evaporator; wherein, the tubular heater is connected with the stock solution groove and used for heat exchange between the stock solution and flash-off steam; the dissolution device comprises a plurality of stages of flash drums, and the last stage of flash drum is connected with the tubular heater; the evaporator is also connected with the tubular heater and used for evaporating the heated stock solution. The system utilizes the flash-off steam which is flash-evaporated by a high pressure dissolution system to preheat the stock solution to be evaporated by using the tubular heater. The technical proposal not only can be used for recycling the flash-off steam to avoid a great deal of energy loss as the flash-off steam is directly exhausted into atmosphere, but also reduces the steam consumed by the evaporator for heating the stock solution.