We have successfully extracted cellulose nanocrystals (CNCs) from seaweed by removing unwanted materials via our modified process. The prepared CNCs were mixed with two biocompatible polymers (polyethylene oxide (PEO)/Eudragit S100). We used the most popular electrospinning method to fabricate a micro/nano-net membrane. The formation of nano-webs between fundamental micro/nanofibers was observed via SEM and TEM, according to the mixing ratio of the solution (PEO:Eudragit: 1:1, 2:1, 3:1 wt:wt%) with 0, 5, 10% CNCs per polymer weight. We found the optimal condition to fabricate nano-net in the membrane and expect it to be applicable for wound healing, tissue engineering, and various filter applications.