Fluid therapy runs throughout the hemodynamic treatment process for ICU patients. A precise fluid therapy strategy is key to implement individualized fluid management and organ protection. A fluid therapy approach guided by fluid responsiveness can help assess the effectiveness, limits, and optimal timing of fluid therapy by evaluating the body's volume responsiveness, fluid tolerance, blood pressure responsiveness, and perfusion responsiveness. This approach enables precise hemodynamic fluid management, identifies patients who truly benefit from fluid therapy, avoids organ dysfunction, and promotes the rapid recovery of critically ill patients.