Study on experimenting to treat acid wastewater from Thien Ke and Tuyen Quang tin processing plants by biological sulfate reduction reaction technology. The result showed that in batch mode, pH increased from 2.8 - 3.2 to 7 - 7.2, sulfate reduction took place positively and produced a large amount of sulfate to precipitate and heavy metals in iron-like wastewater from 143.1 mg / l to 0.3 mg / l, copper from 16.32 mg / l to 0.04 mg / l and manganese from 10.9 mg / l to 0.05 mg / l. Operating in continuous mode with a load of 100 l / h corresponding to the retention time of waste water for three days also results in stable treatment. Post-treatment wastewater has an approximate pH of 7 and 3 types of metal The main pollution is iron, copper and manganese which are eliminated to a concentration lower than 1 mg / l.