Quantum light sources are fundamental modules for quantum communication and optical quantum computation. The quality of quantum light sources directly determines the implementation of quantum key distribution and optical quantum computation. For example, the indivisibility of photons ensures the unconditional security of quantum communication, and the indistinguishability of photons ensures the complexity of computing schemes. Among various solid-state candidate systems, single and entangled photon sources based on solid-state semiconductor quantum dots (QDs) have shown great potential compared to their competitors. Molecular beam epitaxy (MBE) is currently the most suitable technique for growing solid-state semiconductor QDs, with advantages of ultra-high vacuum, ultra-pure materials, in-situ monitoring, and highly controllable growth parameters. To achieve quantum light sources with high efficiency, high single-photon purity, high indistinguishability, and high entanglement fidelity simultaneously, the material growth, external field tuning, surface passivation, and optical measurement techniques of QDs need to be systematically optimized and improved. This article reviews the research progress of basic materials and devices of solid-state QDs systems based on MBE growth. Subsequently, this article discusses the mechanisms of the growth of two types of QDs, the influences of various growth parameters on the quality of QDs, including background vacuum, purity of source materials, substrate temperature, growth rate, beam equivalent pressure (BEP) ratio, etc. After that, this article introduces the technical details and experimental progress of optimizing QDs device performance from the perspectives of external field tuning, surface passivation, and improved measurement technology. Finally, the progress of quantum light sources applications in fundamental scientific problems and quantum network constructions are summarized, and prospects for practical applications and future development are discussed in brief.