Gelatin as a secondary production is obtained from animal wastage such as skin and bones, and is used for food, clinical and other applications. Special properties of gelatin such as biocompatibility and biodegradation have caused this material to be used in pharmacy, cell culture and tissue engineering. Gelatin powder is applied to slow recovering wounds in order to speed up wound recovery. Gelatin is also deployed as cell food in cell culture. Recently, gelatin has simultaneously been applied as cell food and as scaffold in cell culture. Because gelatin has a low biodegradation property, this property must be treated. Different treatments are used for the increasing of the gelatin biodegradation time. These treatments include chemical and physical methods. Here, the crosslinking of gelatin by other monomers is the most important chemical treatment method. In the physical treatment, gelatin blends with other polymers. The increasing of biodegradation time is an essential parameter to apply gelatin in the preparation of the cell culture scaffold. Chemical materials applied to the treatment of gelatin are often toxic. They separate from gelatin during the degradation of scaffolds and menace the cells. Therefor, in this study, the oak-bark tanning agent was selected as a biocompatible material and applied to improve gelatin stability. Oak-bark tannin was extracted in methanol 70% aqueous. Then, the solution was centrifuged to remove solid wood residue. The extract solvent was vaporised in low temperature and vacuum condition, and tannin dried in powder shape. Gelatin was dissolved in a triplet solvent that had been wrought from Acetic acid, water, and ethyl acetate. To study the effect of acetic acid on tannin agent, two solvents were prepared with 40%, 11% acid, 20%, 70% water, 30%, 9% ethyl acetate alternatively. The rest 10% comprised the weight of gelatin in solution. Tannin powder was added to the gelatin solution in 0, 0.5, 1, 2, 3 and 4% concentrations. All solutions were electrospun in (12 kV/10 cm) with 0.15 ml/h. SEM photos prepared from nanofibers showed the electrospinning confine and the effect of tannin concentration on nanofiber diameter. The best range of nanofiber production was between 0.5 to 2% tannin. The best and finest nanofiber was obtained in 10% tannin concentration. The viscometry of these solutions showed that the increasing of tannin concentration led to the increasing of viscosity by the creation of hydrogen bonds between tannin and gelatin. The prepared nanofibers were dried under a special condition for later experiments. Due to the thermal sensitivity of tanning agent, the reaction between gelatin and tannin was performed at low temperature. In addition to viscometry, other analyses such as biodegradation test, DSC and FTIR were helpful devices to determine whether tannin agents reacted with gelatin or not. DSC showed that the increasing of tannin concentration would lead to the disappearance of the peak in glass transition and melting point. In this process, the decomposition peak was intensified as well as shifted to higher temperature. These results demonstrated that tanning agent improved the physical stability of gelatin. Therefore, IR spectroscopy showed that gelatin had crosslinked with a lot of hydrogen bonds and the stability of gelatin nanofibers had increased. Keywords : gelatin, vegetable tannin, electrospinning, crosslink, biodegradation