Excellent vacuum performance ensures a high beam transmission efficiency of theneutral beam injector (NBI).The vacuum performance is mainly determined by the cryoperfor-mance of the cryopanel of the cryocondensation pumps which are the main vacuum pumps of NBI.In order to optimize the cryoperformance,the requirements for the temperature distribution andthe heat load of tire cryopanel are analysed and the factors that affect the cryopanel’s temperaturedistribution are studied.The results indicate that.tire temperature difference of the cryopanel canbe reduced by fabricating the eryopanel with high thermal conductivity material,increasing itsthickness and cutting the distance between the two upward cooling pipes.The results may beapplied to a cryopanel cooled by forced flow liquid helium. Excellent vacuum performance ensures a high beam transmission efficiency of the neutral beam injector (NBI). Vacuum performance is mainly determined by the cryoperfor-mance of the cryopanel of the cryocondensation pumps which are the main vacuum pumps of NBI. Order to optimize the cryoperformance the requirements for the temperature distribution and the heat load of tire cryopanel are analysed and the factors that affect that cryopanel’s temperature distribution performance are that the indicates that the temperature difference of the cryopanel canbe reduced by fabricating the eryopanel with high thermal conductivity material, increasing itsthickness and cutting the distance between the two upward cooling pipes.The results may beapplied to a cryopanel cooled by forced flow liquid helium.