We present exact coupled-channel (CC) results of full-dimensional quantum mechanical calculations for the H + D 2 O / D + HOD exchange reaction which provide the first evidence for a shape resonance in this reaction, employing the initial state-selected time-dependent wave packet method with both OD bonds in the D 2 O reactant treated as reactive bonds. Due to the shallow C 3v minimum along the reaction path, the signature of shape resonance is manifested as the existence of a distinct step-like feature in the CC integral cross sections of the exchange reaction just above the threshold. Our study also shows that the current CC integral cross sections are in very good agreement with the experimental results, and a bit larger than those calculated in the previous quantum dynamics study, where the one reactive bond and centrifugal sudden (CS) approximations were invoked, revealing that the one reactive bond approximation overestimated, while the CS approximation underestimated the integral cross sections.Reactive scattering resonance has been a central topic in the study of chemical reaction dynamics during the past few decades.1-7 In a typical chemical reaction, the transition state is an energy maximum along the reaction coordinate, and so it does not persist as a discrete structure. However, in certain cases, a reaction complex in the transition-state region could be transiently trapped in vibrationally adiabatic wells along the reaction coordinate. Such a transiently trapped quantum state along the reaction coordinate is normally called a Feshbach resonance, or dynamical resonance.4-8 Significant efforts have been devoted to investigating the structures and dynamics of Feshbach resonances in chemical reactions, and the F + H 2 reaction has proven to be a truly benchmark system for dynamical resonances. Since the first theoretical prediction of reaction resonances in the F + H 2 reaction in the early 1970s, 9-11 the search for evidence of such resonances in this reaction has attracted much attention from many top research groups in this field.12-20 Recently, the F + H 2 (HD) reaction was studied extensively in an effort to understand the dynamical resonances in this important system, 8,21-23 using the high-resolution crossed molecular beams technique in combination with full quantum scattering calculation based on accurate potential energy surfaces. The advances made in these studies have provided a clear physical picture of dynamical resonances in this benchmark system that has eluded us for decades.It is precisely the couplings between the reaction coordinate and various degrees of freedom of the system that are perpendicular to the reaction coordinate that are responsible for dynamical (Feshbach) resonances. However, there is another type of reactive scattering resonance, for which the interactions of the various collective modes of the molecule are not taken into account. Merely depending on the depth and width of the well along the reaction path, several quasi-bound quantized states may be transiently trapp...