Due to their atomic-level thickness and unique optoelectronic properties, the transition metal dichalcogenides (TMDs) have been received widespread attention and research. The controllable preparation, novel optoelectronic properties and optoelectronic applications in many fields, such as photodetection, light emission, spin and energy valley electronics of TMD, have been reported widely. From the three perspectives of material preparation, optoelectronic properties and applications of TMD, these works are reviewed.