A facile strategy combining ultrasonication and high-efficient hot-pressing technique is proposed to largely fabricate a thinner conductive composite film with excellent electromagnetic interference (EMI) shielding performance by employing graphene nanosheets to decorate porous cellulose aerogels (CA). Morphology examination reveals that a three-dimensional sheet-like skeleton network with highly oriented layered structure along the plane direction is perfectly constructed in the prepared CA composite film, which endows the prepared composite film with a high electrical conductivity of 91.2 S/m, excellent EMI shielding effectiveness (SE) of 49.5 dB and impressive normalized surface specific SE of 1509.6 dB·cm²/g at a thickness of only 0.6 mm. Also, the obtained composite film achieves good mechanical fastness and chemical durability, including the excellent resistance to ultrasonic treatment (60 min), tape adhesion (1000 cycles), and pH tolerant tests (pH =2.0/12.0 for 24 h). This work provides a feasible and novel strategy for fabricating high-efficient EMI shielding performance composite film that suitable for high precision and sensitive electronic instruments even under harsh environment.