Background　Numerous studies have demonstrated that goal?蛳directed fluid therapy（GDT） is contributed to decreasing postoperative complications and improving clinical outcome. Dynamic variables， such as stroke volume variation（SVV）， pulse pressure variation（PPV）， pleth variability index（PVI） and PPV/SVV， have been shown to be reliable predictors of fluid responsiveness in mechanically ventilated patients under general anesthesia. They are superior to static variables in guiding perioperative fluid management.　Objective　To discuss the reliability and influencing factors of dynamic variables in goal?蛳directed fluid therapy.　Content　Dynamic variables can be significantly influenced by tidal volume， vascular tone and patient position. Besides， the ultimate aim of fluid therapy is ensuring optimal tissue perfusion and oxygenation for patients rather than improving any variable. Therefore， dynamic variables can be made increasingly more sensitive and specific if combined to other hemodynamic variables， relevant laboratory results and prognosis.　Trend　Dynamic variables have broad application prospects in guiding perioperative fluid management. However， the ability of dynamic variables in evaluating organ perfusion still needs further research.