The invention discloses a waste acid regeneration device and a waste acid regeneration process. The waste acid regeneration device comprises an absorption tower, a regenerated acid tank, a water collection tank, a bleaching tank as well as a bypass tubes wherein the outlet of the absorption tower is connected with the inlet of the regenerated acid tank; a first valve for controlling regenerated acids fed into the regenerated acid tank is arranged on the absorption tower; the outlet of the water collection tank is connected with the inlet of the absorption tower; the outlet of the absorption tower is connected with the inlet of the water collection tank; a second valve for controlling water to flow back to the water collection tank is arranged on the absorption tower; the outlet of the bleaching tank is connected with the inlet of the water collection tank, and then water can be constantly supplied into the water collection tank; the bypass tube is arranged at the outlet of the absorption tower and the inlet of the bleaching tank; a third valve is arranged on the bypass tube. In a water operation mode, the first valve is closed, the third valve is opened, the opening degree of the second valve is adjusted according to liquid levels of the water collection tank, and furthermore the phenomenon of water tank overflowing is avoided.