Cellulose nanopaper has attracted tremendous attention as an alternative to fossil-based flexible substrates. However, the fabrication of nanopaper from cellulose nanofibers (CNFs) is a time-consuming process. Herein, positivelycharged CNFs (PCNFs) were employed to heterocoagulate negatively charged CNFs (NCNFs) at various PCNF-to-NCNFratios in order to decrease the formation time of nanopaper. At a PCNF-to-NCNF ratio of 1:1, the formation time was reducedfrom 98 min to 20 min. Although heterocoagulation increases the roughness of cellulose nanopaper, nanopapers made from amixture of NCNFs and PCNFs still possess a nanosized network structure and therefore show similar transparency tonanopapers made of pure NCNFs. Compared to the nanopaper made from pure NCNFs, the nanopaper made from themixture of NCNFs and PCNFs showed reduced tensile strength but improved resistance to deformation. This study providesa practical method for the production of cellulose nanopaper.