Recent progress in angle-resolved measurements of desorbing surface reaction products is reviewed. The angular and velocity distributions of desorbing products deliver the most direct structural information of the reaction site when the products are repulsively desorbed. These distributions yield the symmetry and slope of the product formation site as well as the orientation of the intermediate species emitting the product. This method works well even when the overall reaction rate is controlled by the reactant adsorption and the interaction between adsorbed species is obscured in kinetic studies at the steady-state conditions. However, information about the reaction mechanism is requisite for its application because the method is linked directly to the reaction itself. Analysis of the product formation site and its switchover is exemplified in a steady-state CO + O₂ reaction on platinum, and the product emission in the NO reduction on palladium is described.