Abstract: The influencing factors of defluorination in the single-step decolorization and defluorination technology of wet-process phosphoric acid (WPA) with activated carbon and Na<SUB>2</SUB>CO<SUB>3 </SUB>as decoloring agent and defluorinating agent were studied.Take Gore membrane as the filter medium,the best technological conditions of defluorination were drawn on the basis of experiments:reaction temperature was 70 ℃,reaction time was 90 min,dosage of activated carbon was 0.3%,dosage of Na<SUB>2</SUB>CO<SUB>3</SUB> was 2% of wet-process phosphoric acid,and sedimentation time was 1 d.Under these conditions,the defluorination rate reached above 70%.