One of the serious complications that have not been solved yet in modern medicine is a postoperative tissue adhesion of internal organs. Tissue adhesions are associated with numerous postoperative complications, including pain, functional obstruction and difficult re-operative surgery. In this study, poly($gamma$-glutamic acid)($gamma$-PGA) based nanofiber sheets were prepared by using electrospinning technique to evaluate the ability of the prevention of postoperative tissue adhesion. The anti-adhesion membranes were prepared from $gamma$-PGA and poly(D,L-lactic-co-glycolic acid)(PLGA) with different compositions by electrospinning. Also non-steroidal anti-inflammatory drug (ibuprofen) was incorporated during fabrication of nanofibers. Various electrospun nanofibers were characterized by SEM, FTIR, water contact angle measurement, biodegradability test, in vitro drug release profile, cell culture test, and in vivo animal study using Sprague Dawley rat model. The average diameter of the nanofibers electrospun from the various biodegradable polymer solutions ranged from 300 nm to 900 nm, approximately. From in vivo animal study, it was observed that ibuprofen-incorporated $gamma$-PGA nanofiber sheet (crosslinked) was significantly effective in preventing post-surgical tissue adhesion and wound healing, probably due to the appropriate hydrophilicity preventing shrinkage of the sheet. On the other hand, PLGA nanofibrous mat was dramatically contracted in vivo due to its high hydrophobicity and resulted in insufficient coverage of wound.