As a well-known industrial fungus for cellulase production, the strain RUT-C30 of Trichoderma reesei was selected to produce the feruloyl esterase A (FAEA) by a random integration protocol. The strong promoter of cellobiohydrolase 1 (cbh1) gene was used to drive the expression of FAEA. Using double-joint PCR protocol, Pcbh1-faeA-TtrpC expression cassette was successfully constructed and co-transformed into RUT C30 strain of T. reesei. One transformant with high feruloyl esterase yield (3.44 +/- 0.16 IU/mL) was obtained through plate screening and named TrfaeA1. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of fermentation supernatant from transformant TrfaeA1 showed a distinct protein band appearing at the position of about 34 kDa, indicating that faeA gene has been successfully expressed in T. reesei. Compared with that in original RUT C30 strain, beta-glucosidase production in transformant TrfaeA1 was significantly increased by about 86.4%, reaching 63.2 IU/mL due to the random insertion of faeA. Moreover, the total secretion protein and filter paper activities of the transformant TrfaeA1 were also improved by up to 5.5 and 4.3%, respectively. The present results indicated that the random insertion strategy could be an effective and feasible method to improve and optimize the cellulase system of filamentous fungi.