Utilizing solar power has become more common in most regions among several renewable energy sources that are currently available, including geothermal, wind, biomass, and tidal etc. Hence, researchers are turning their attention to solar energy studies. Solar thermal collectors have the ability to capture solar energy. Various solar collectors have already been modelled, designed, built, and tested to perform in a variety of temperature ranges, including low temperature collectors (compound parabolic collectors 60-240°C, evacuated tube collectors 50-200°C, and flat plates 30-80°C), medium temperature collectors (parabolic trough 40-400°C, cylindrical trough collector 60-300°C, and linear Fresnel reflectors 60-250°C), and high temperature collectors (heliostat field collector 150–2000°C and parabolic dish reflector 100–1500°C). The parabolic trough collectors (PTCs) have been discovered to be the most popular between the various solar collectors in applications such as the steam generation, the delivery of process heat, and desalination. Since about three decades ago, various theoretical and experimental research studies have been carried out in order to improve the thermal and optical efficiency of the PTC system. This review studies the parameters influencing the PTC thermal performance and the enhancements to improve the design modification, optical, and thermal properties used in PTC.