Carbon dots (CDs) have attracted widespread attention because of their excellent properties and various preparation methods. Solvothermal methods have the advantages of simple operations, high product yields, and low costs, which have become the most commonly used methods to synthesize CDs. Understanding the effects of the solvent on the properties of CDs will allow the advantages of CDs to be fully utilized and promote their applications. This review summarizes the effects of reaction solvents on the morphology and properties of CDs, as well as the regulation mechanism of the dispersion solvent on the optical properties of CDs. On this basis, the applications of solvent-engineered CDs in sensing, imaging, optoelectronics and photocatalysis are introduced. Furthermore, we discuss the existing problems and prospects of solvent-engineered CDs.