During the past few years, study of the all-solid-state blue laser has been focused on laser field applications in many fields and potential value of commerce. There has been much work done in order to obtain an efficient and simple solid-state blue laser source, this device being of interest for applications such as display technologies, production of high-density optical disk systems, high-resolution printing, or medical diagnostics. This paper discusses three means to realize all-solid-state blue lasers, including blue-emitting diode laser, direct frequency doubling of infrared laser diode (LD), diode-laser pumped all-solid-state blue lasers, respectively. However, direct emitters based on II - VI semiconductors are limited by the lifetime of laser diode. A practical and the most used way is the frequency-doubling of the 946-nm in Nd:YAG. In the field of nonlinear frequency conversion, we compare some different frequency-doubling crystals with improved optical characteristics, including higher nonlinear coefficient, wider transmission range, and more flexible phase-matching (PM) properties. Some nonlinear optical crystals usually used in solid-state laser are analyzed and compared, including KNbO3, LBO, BBO, BiBO, CBO (CsB3O5), KBBF (KBe2BO3F2). The recent progress on solid-state blue laser has resulted research in from gain media, frequency-doubled crystals, and configurations of the cavities. Two difficulties which are the coating techniques and the blue noise problem (the fluctuation of the laser output power) in the development of solid-state lasers are pointed out, and the techniques of solving blue noise problem that have been usually used in the past research are presented.