This paper presents an overview of the research progress on the quantum-dot lasers. The structure growth and optimization of quantum-dot lasers are introduced firstly, then the optoelectronic properties are discussed in the term of spectrum and modeling, and the dynamic characters of quantum-dot lasers such as homogeneous broadening of optical gain, lasing spectrum control, transition property of excited state etc., are presented based on rate equation. The outlook of the future works on quantum-dot lasers is given finally.