The flow characteristics in confined impinging jet reactors (CIJRs) were investigated, using particle image velocimetry. The effects of Reynolds number (Re), jet velocity ratio (u(1)/u(2)), jet diameter (d), and the factor L (defined as the distance between the axes of two jets and the top wall of the CIJR chamber) on the flow characteristics of CIJRs were discussed. The similarity of the turbulent flow in CIJRs was extended to the operating conditions with high Reynolds numbers, ranging from Re = 10 620 to Re = 21 210. The position of the stagnation point in CIJR is closely related to u(1)/u(2), but independent of d. The decrease of the ratio of the factor L to impinging jet diameter (L/d) from 4 to 1.5 can increase the values of turbulent kinetic energy and intensify momentum transfer and mixing in the impinging region of CIJR. The present study shows that CIJRs are ideal reactors for rapid chemical reactions, and optimized parameters are helpful for the design and operation of such reactors.