Objective Photochemical reaction of Zingiber officinale extract catalyzed by curcumin, and antimicrobial activities of the extracts before and after illumination were studied. Methods Disk diffusion test was applied to test the antimicrobial activities of the extract without curcumin after illumination, the extract containing curcumin after illumination, and that containing curcumin without illumination, against 23 kinds of microbial pathogens. TLC and HPLC were applied to detect the changes of the components in the Zingiber officinale extract after illumination, with or without curcumin. Results The antimicrobial activity of the illuminated extract containing curcumin increased significantly, especially the activities against MRSA and Mycobacterium smegmatis increased drastically. TLC and HPLC revealed that the components in Zingiber officinale extract containing curcumin changed significantly after illumination. Conclusion Under the catalysis of curcumin, some compounds in Zingiber officinale underwent photochemical reaction after illumination. As a result, products with much higher antimicrobial activity were generated.