Abstract: Semiconductor quantum dots (QDs) are new inorganic fluorophores that are currently being investigated for use as luminescent biological probes in biology due to its unique optical properties. The fluorescence excitation and emission properties, quantum yield, photobleaching characteristic and fluorescence lifetime of quantum dots are described in detailed. Particularly, this review summarizes the recent advances of quantum dots in developmental biological applications, which mainly including cellular labeling, in vivo animal and tissue imaging, multiplexed assaying and photodynamic therapy. Moreover, the potential toxicity and challenges of quantum dots in biological application are discussed. Finally, the future prospects for promising applications of quantum dots in biology will be also briefly presented.