A thin layer of silver was prepared on cellulose film (CF) surface via electroless plating to obtain high electromagnetic shielding effectiveness Ag/cellulose composite layer. The process is simple, efficient and low-cost. The developed film has a great advantage in electric conduction and electromagnetic interference (EMI) shielding. The identical deposit of thin silver layer was perfectly fabricated via the electroless plating on the CF surface. The fabricated thin silver layers were tested for electrical properties and EMI SE. The electrical and electromagnetic shielding properties of the thin silver layer were ideal when the activation concentration was 100 Mm (mmol/L). Herein, the resistance and conductivity of Ag/cellulose composite films can reach 0.35 Ω and 45 s/cm, respectively, and the EMI SE of Ag/cellulose composite films can be up to 67 dB ranging from 0.0003 to 3 GHz. The dielectric constant (ε′) of the Ag/cellulose composite film was between 6.5 and 7.5, which was stable throughout the test band ranging from 2 to 18 GHz. The permeability (µ′) of the Ag/cellulose composite film was around 1 ranging from 2 to 18 GHz.