Polycentric planning strategies have often failed to achieve the expected effects. The ensuing uncertainty associated with the desirability of polycentric strategies is also reflected in the early literature which offers no clear conclusion about whether the polycentricity affects economic performance and how. This paper aims at offering a clear conclusion about it, especially its dependence on city size. Against this backdrop, we conceptualize polycentricity as a process of reclustering after decentralization to reevaluate its impact on performance. To this end, we use the city proper level Chinese Economic Census (2004, 2008, and 2013) and apply a fixed-effects panel model, the results of which show that the dependence of the urban economy on spatial structure is contingent on city size. More specifically, both decentralization and clustering (and therefore the polycentric structure) facilitate economic performance only when cities reach a certain size. We use our findings as the basis for outlining an emergent research agenda for urban polycentricity.