As one of the nanostructures of the most important elemental semiconductorsilicon, silicon nanocrystals have attracted great research interests given their remarkable optoelectronic properties and environmental friendliness. In the past decades, tremendous work has been carried out to understand the quantum confinement effect, surface effect and doping effect of silicon nanocrystals and to modify the electric and optical properties of silicon nanocrystals for the purpose of applications in printed electronics, siliconbased optoelectronics and biocompatible highperformance optoelectronics. Up to now, typical optoelectronic devices based on silicon nanocrystals including solar cells, lightemitting diodes and photodetectors have been successfully fabricated. The paper summarizes the recent progress obtained on the investigations of the synthesis, properties and optoelectronic device applications of silicon nanocrystals. In addition, we outlook the perspective of silicon nanocrystals with desirable properties for highperformance device applications.