Indoor air pollution is one of the significant inducing factors of some diseases, such as leukemia, tumors, respiratory disease, and kidney failure. Among these contaminants, formaldehyde has a long release span and is a great threat to our health. However, methods for formaldehyde elimination and detection are limited. Herein, a new paper-based multifunctional fluorescent material was developed for the simultaneous high-efficiency removal and detection of formaldehyde. The paper-based material was fabricated using polyethyleneimine (PEI) and a highly sensitive ratiometric fluorescent probe (FP). The paper-based material can detect formaldehyde with a significant change in fluorescence: the fluorescence at 450 nm decreased by over 75 %, and the fluorescence of FP in the ratiometric channel increased by over 100-fold. Moreover, the formaldehyde elimination rate is up to 99 %. By combining the porous network structures of paper, the abundant amino groups in PEI, and the highly sensitive fluorescent response of FP, the multifunctional fluorescent paper material can be effectively utilized for formaldehyde removal and detection.