It is well known that arch is a main part of the historical structures. Therefore, many techniques are used to strengthen these arches. In this paper, Fiber Reinforced Polymer (FRP) is used to reinforce the arch under vertical loads. Materially Non-Linear Analysis (MNLA) is performed to demonstrate the behavior of the arch with and without the FRP. On the other hand, the effect of FRP lamina thickness and length is undertaken in this research. This paper shows that a small amount of the FRP to some local areas can enhance the ultimate strength of the arch significantly.