Supermassive black hole binaries(SMBHBs)are the products of frequent galaxy mergers.The evolution of SMBHBs is very important because the supermassive black holes(SMBHs)in active galactic nuclei(AGNs)play a key role on the formation and the evolution of their host galaxies through feedbacks.Moreover,before and during the coalescence of the SMBHB,there are particularly gravitational wave(GW)radiations,which can help us to investigate the GWs and general relativity.Thus,the detections of the strong GW radiation and their possible electromagnetic counterparts are essential.By using one million particle direct N-body simulations on special many-core hardware(GPU cluster),we study the dynamical coevolution of SMBHB and its surrounding stars in gas poor environment,specially focusing on the evolution of stellar tidal disruption rates in the galactic nuclei before and after the coalescence of the SMBHB.Our results show that there is a boosted tidal disruption rate during the merger of the galaxies.And we also find out a special tidal disruption light curve in SMBHB system,which can be used to identify such kind of systems.After the coalescence of two SMBHs,as predicted by numerical relativity,the post-merger SMBH may get a kick velocity up to several thousand kilometers per hour due to the anisotropic GW radiations during the coalescence.Our results about the recoiling SMBHs which are oscillating around galactic center show that most of stellar tidal disruptions are contributed by the unbound stars and occur when the oscillating SMBHs pass through the galactic center.The averaged disruption rate is~10-6 M⊙ yr-1,which is about an order of magnitude lower than that by a stationary SMBH at similar galactic nuclei.