The utility model provides a flexible direct current change of current valve water cooling system is automatic with salt device, its characterized in that: including base, motor, salt hopper, transmission pipe and salt case, motor and salt hopper are fixed respectively on base upper portion, the salt hopper bottom is provided with a discharge gate, discharge gate and transmission pipe access connection, the export of transmission pipe is relative with the import of salt case, the controlled end and a MCU of motor are connected, still include a conductivity sensor, the conductivity sensor probe passes the salt case, conductivity sensor probe output with MCU connects. The utility model discloses can realize automatic transporting the salt case with salt from the eminence, realize the automatic salt that adds, on the other hand leads to filter cap protection conductivity sensor probe, the salt case utilization ratio of improvement, and the extension is with the salt cycle, and the reduction is with the salt frequency.