Abstract: Based on the design characteristics of WWER-1000 type reactor and the operation practice,this paper describes the characteristics of the fuel assembly of WWER-1000 and compares with PWR in western countries.Especially,this paper analyzes the bowing performance of the fuel assembly of WWER-1000 and the bowing influence on the thermo-hydraulics and fuel assembly design,and clarifies the experimental results of the bowing effect on the critical heat flux density（CHF）,which confirms that the performance of WWER-1000 fuel assembly in the entire operation life can be guaranteed.