Abstract: The combined method of adsorption-reduction is a promising method for chromium pollution control. In this paper, nanocellulose-polyethylenimine-polypyrrole (CPP-F) photosensitive composite aerogel was prepared by in-situ oxidation polymerization of pyrrole using nanocellulose-polyethylenimine aerogel (CPA) as skeleton. The aerogel was characterized by SEM, FTIR, UV-vis and XPS. The adsorption, in-situ reduction and cyclic adsorption properties of CPP-F composite aerogel on Cr(VI) were studied by comparing the dark and light conditions, and the cyclic adsorption mechanism was analyzed. The results show that CPP-F is a black porous aerogel with uniform and stable structure, and has strong light absorption effect in ultraviolet, visible and near infrared region. After light treatment, Cr(III) content in Cr(VI) loaded CPP-F increase from 29.76wt% under dark conditions to 72.33wt%, and its reduction rate is 2.43 times that of dark conditions, indicating that polypyrrole (PPy) has excellent photocatalytic performance, and light treatment can promote the in-situ reduction of Cr(VI). After 6 cycles of adsorption, the cyclic adsorption capacity of Cr(VI) by CPP-F under light treatment is 64.97% higher than that under dark treatment, indicating that photocatalytic reduction of Cr(III) provides a new adsorption site for Cr(VI) and realizes the cyclic adsorption of Cr(VI). The combination of adsorption-photocatalytic reduction-cyclic adsorption has more advantages than adsorption method, and has great application potential in Cr(VI) pollution control.