I− ions doped (BiO)2CO3 (denoted as I-BOC) was prepared by a facile and rapid solid-state chemical reaction route. As compared to pure BOC, the I-BOC exhibited excellent visible-light-driven photocatalytic activity for rhodamine B (RhB) degradation even when RhB concentration reached 20 mg/L (catalyst, 0.4 g/L). Furthermore, the as-prepared I-BOC also exhibited good visible light photocatalytic activity for the degradation of methylene blue (MB), crystal violet (CV) and salicylic acid (SA). The investigation on the photocatalytic mechanism indicated that the doping of I− ions decreased the particles size and band gap simultaneously, which resulted in an increase in the exposed active centers and visible light absorption range, thus enhancing visible light photoactivity.