Abstract: In this paper an acidic precipitation agent bearing mercapta was used to capture heavy metals (including Cu, Pb, Sn and Fe) from the HNO₃-type wastewater in the solder stripping process of PCB factories. The experimental results showed that the feasible precipitation factors are: the precipitation agent is added by the chemically calculated amount to the wastewater with stirring and accompanying of 12 g/L SO₂and 3～5 mL of 1% PAM (MW=400 000), respectively. The regenerated solution after filtration was as good as the fresh stripping solution in its stripping properties such as stripping rate and stripping capacity, etc. In other words the stripping wastewater can be recycled in the PCB enterprises.