Zinc oxide (ZnO), as a typical wide bandgap (3.37 eV) semiconductor, has abstracted increasing interests in optoelectronics field. Its large exciton binding energy of 60 meV endows it with high radiative recombination efficiency, which is a unique advantage in light emitting and lasing devices. After more than a decade of developments, the thin film growth, doping and the device study have achieved much improvement. In this review, we introduce a part of results on the above aspects in the last five years. In these improvements, the ones achieved by the "973" project group (2011CB302000) are shown in detail. So far, their jobs cover hertero- and homo-epitaxy of thin film, interface and surface engineering, carrier transport, energy engineering, p-type doping and optoelectronics devices. They have realized the 2-D growth of thin film, epitaxial growth on silicon, solar blind UV detector, LED with dozens-hour continual-operating time, and lasing device with controllable mode. These advancements are expected to accelerate the process of practical applications of ZnO.