Abstract: Acceleration of the shock generated by normal reflection of gaseous detonation wave was experimentally, numerically and theoretically investigated. The pizeo-electric transducers were employed to obtain the pressure history at the specific port. Based on two-dimensional reactive Euler equations and detailed chemical reaction model, numerical simulation was performed. The 2nd additive semi-implicit Runge-Kutta method and 5th order WENO scheme were respectively used to discretize the time and space terms. The numerical pressure history at the specific port was also obtained. Based on detonation theory and shock dynamics, the complicated wave evolution involved in the process of gaseous detonation reflection was analyzed and the velocity of reflected shock was obtained. The results show that numerical simulation and theoretical analysis qualitatively reproduce and explain the experimental phenomena. After gaseous detonation reflects on the right wall, the right-traveling rarefaction waves accelerate the reflected shock. The reason is that the shock Mach number increases and the gas flow velocity ahead of the shock decreases even though the acoustic velocity ahead of the shock decreases. Possibly due to the left unreacted or partly reacted mixture behind gaseous detonation wave, the reflected shock accelerates at low initial pressure more than at high initial pressure.