This study applies the stochastic frontier approach to estimate the technical efficiency of a group of Chinese cities which have hosted mega events such as the Olympic Games and Asian Games, etc. since 2000s. The purpose is to assess if their efficiency level can be strengthened in the process of event preparation. In the empirical analyses, it is observed that no significant improvement on technical efficiency can be achieved by the event hosting cities. The level of technical efficiency of the event hosting cities has even slightly declined in the event decade. Investment to gross domestic product (GDP) ratio is found to have positive linkages with technical efficiency, but it has not expanded satisfactorily to bring about significant efficiency improvement. Economic transition toward service sector with no comparative advantage, meanwhile, tends to discount efficiency. In general, hosting an event can only bring about short-lived contributions to economic benefits but not significant efficiency improvement. Policy makers should be cautious in the future before making their decisions to host mega events.