An optical fragile watermarking method is proposed based on visual cryptography and QR code for image authentication and tamper detection. On the one hand, the original image is transformed into a QR watermark image to improve the watermark hiding capacity. On the other hand, the visual cryptography and optical phase coding are fused to encrypt the watermark image to enhance system security. The feasibility, vulnerability and imperceptibility of the proposed scheme are tested through a series of attacks and tampering. The simulation results show that the proposed method can not only have good imperceptibility, but also achieve high detection performance under different attacks and tampering.