The effect of defect on the photocatalytic and photoelectric performance of BiPO4 has been revealed. The bulk defects of BiPO4 such as bismuth vacancies (V-Bi), oxygen vacancies (V-o) and so on were formed during the ball-milling process. These bulk defects of BiPO4 inhibited the separation of photo-generated charges greatly and thus reduced photocatalytic activity. Most of the bulk defects were repaired and the photocatalytic activity of BiPO4 was also recovered mostly via calcination and reflux. Reflux could repair the bulk defects of BiPO4 much better than calcination. The mechanism of the photocatalytic degradation of pollutants over BiPO4 was not changed by defects, and the main oxidation active species of BiPO4 is photo-generated hole. (C) 2016 Elsevier B.V. All rights reserved.