In recent years, with the adaptation of nanotechnological engineering applications to complex systems, the use of nanofluids with better thermo-physical properties compared to conventional fluids has become widespread. In addition, studies on the preparation techniques of nanofluids, improving their thermal properties and evaluating their thermal performance are increasing. This study presents a review about preparation, evaluating and enhancement of the stability and thermal properties of nanofluids. Furthermore, the recent advances about the thermo-hydraulic, thermodynamic and thermo-economic performances of nanofluids in different types of thermal systems are summarized as well. The stability of nanofluid is a significant factor affecting its applicability. Various techniques have been used in the literature to enhance the stability of nanofluids such as surfactant addition, ultrasonic mixing and pH control. By using nanofluids, the desired thermo-physical properties can be obtained in order to improve the heat transfer property in the system. Some researchers recommend to hybrid nanofluids because of the hybrid effect of two or more particle types they contain. The reviewed literature also indicates that the use of nanofluids instead of conventional working fluids is an effective way to increase the thermo-hydraulic performance of thermal systems. In addition, according to the literature review, minimum entropy generation is an effective way to increase the energy efficiency and improve thermodynamic performance of the thermal system and the use of nanofluids provide a significant reduction in entropy production.