The utility model discloses a purification and dust removal system, purification and dust removal system includes desulphurization unit and is used for purifying the warp wet -type electrostatic precipitator device (1) of the flue gas after desulphurization unit handles, wherein desulphurization unit is sea water desulphurization unit (2). The utility model provides a purification and dust removal system can not produce the gypsum granule, and the dust concentration of wet electrostatic precipitator entrance is lower, has alleviateed wet electrostatic precipitator's dust removal pressure greatly to can reduce the inside anode plate of wet electrostatic precipitator and harden, block up and the emergence of scheduling problem of wearing and tearing, thereby can improve the dust collection efficiency effectively.