As the arch structure is one of the common structural forms of underground engineering， the majority of current research focuses on the numerical simulation. The numerical results of structural damage characteristics and response lack corresponding experimental verification， which cannot sufficiently guide the blast resistance design of underground engineering. In order to study the failure mode and blasting resistant performance of underground arch structures with reinforced concrete under explosive load， 5 independent experiments under top explosion had been carried out with different blasting distances and charges. Results show that the damage degree of the arch structure gradually increases with the increase of charge under the same blasting distance. The characteristics of failure mode developed from the concrete cracks at the back surface of blast to the concrete spalling and deformation of steel bars. At last， the concrete collapsed significantly at the center of the vault and the steel bars were severely bent and deformed. The damage of the arch structure under top explosion is not only related to the scaled distance， but also affected by the blasting distance. Under the same scaled distance，the damage degree of arch structure increases significantly with the increase of blasting distance. By analyzing the relationships between the displacement response and the charge mass， the displacement response and the blasting distance， a method is initially proposed for dividing the damage grade based on the deflection-span ratio， which provides experimental support for the structural failure evaluation and analysis in the future.