Abstract: The liquid metal cooled fast reactor has significant strategic significance for the innovative development of nuclear energy, and the development of fuel performance analysis programs suitable for liquid metal cooled fast reactors is of great significance for the design and safety analysis of fast reactors. Fuel elements are one of the most fundamental components of nuclear reactors, and analyzing their performance is one of the most challenging tasks in reactor development. The fuel element performance analysis program LoongCALF based on the multi-physics coupling platform MOOSE was developed in this paper. This program aimed to simulate the long-term service performance evolution of fuel elements under steady-state conditions, providing scientific basis for the design, service life prediction, and safety evaluation of LMFR fuel elements. The program was aimed at metal cooled fast reactor fuel elements, and based on finite element method and JFNK method, solved the thermal mechanical coupling equation of nuclear reactor fuel, and obtained the spatial distribution and temporal variation of physical quantities such as temperature, stress, strain, and fission gas release. The program used a 1.5-dimensional modeling method to perform multi-physics field coupling calculations on fuel rods. In addition, the program supported one-dimensional, two-dimensional, and three-dimensional mesh modeling calculations to meet the construction requirements of fuel element models of different sizes and shapes. The program adopted a modular design with separate material modules. Currently, the fuel types supported by the program include UO₂ and MOX, the cladding materials include HT9 and 1515Ti, and the coolant materials supported sodium, lead, and lead bismuth. To verify the accuracy of the program, two benchmark examples were designed for numerical simulation and calculation in this paper. Example 1 used UO₂ as the core material and 1515Ti as the cladding material; Example 2 used MOX as the core material and HT9 as the cladding material. By comparing and calculating with the Fiber-Oxide program of the Chinese Institute of Atomic Energy, it is found that the two programs show good consistency in key parameters such as core cladding temperature, displacement, stress, and fission gas release fraction. Although there are certain differences in the handling of repositioning and fracture models, resulting in some deviation in the initial calculation results, considering the limitations of the empirical models used in fuel performance analysis programs, this difference is still within an acceptable range. In summary, the LoongCALF program can accurately simulate the fuel behavior and key parameter evolution inside fuel elements under steady-state operating conditions of liquid metal cooled fast reactors. In the future, we will rely on more practical measurement cases to conduct deeper verification and optimization of the LoongCALF program, to ensure its accuracy and reliability in fast reactor design and safety analysis.