Nanooptics is a new frontier and fundamental direction generated by the intersection of photonics and nanotechnology, which enables people to manipulate the interaction between light and matter at the nanoscale and explore new physical phenomenons. Nanolaser is a new kind of light source and its research is an important branch in the field of nanooptics. Since the feature of small size and strong confinement, nanolasers have attracted more and more attentions from researchers in recent years. In this paper, some exciting progresses in laser miniaturization are reviewed. First, we briefly describe various new types of lasers realized in recent years and their characteristics. Second, the new physical problems of micro- /nano-lasers are analyzed and the latest progresses are presented. Finally, some technical challenges in the application of nanolasers are introduced and considered.