Abstract: Very High Temperature gas cooled Reactor (VHTR) has a wide range of applications such as hydrogen production by nuclear energy. Depressurized Loss of Forced Cooling accident (DLOFC) is one of the most severe design basis accidents of VHTR. It may cause large cost to analyze the DLOFC with large amount of different parameters using the Full Order Model (FOM). It is of vital importance for calculating DLOFC accident accurately and quickly within the scope of the design parameter which is also a great need for design of VHTR. This paper constructs a FOM for VHTR based on TINTE and a Reduced Order Model (ROM) which can calculate the DLOFC accident of VHTR based on POD-RBF. This paper proposes two ROM methods for calculating the transient process of DLOFC. One is to consider the time equal to input temperature etc. of perturbation parameter. The other one is to calculate the coefficient of whole time for DLOFC of one parameter at one time. The results show that the maximum relative error of both methods is less than 1%, and the computation efficiency of ROM is much higher than that of FOM. At the same time, method 2 is 40 times more efficient than method 1.