Abstract: The reactor core is a multi-physical and multi-scale coupled system. Many physical phenomena such as neutronics, thermalhydraulics and fuel affect each other. The goal of the coupling software is to truly simulate the reactor core through the physical models of core neutronics, thermalhydraulics, fuel and the interaction of various physical fields. The coupling framework solves the common problems of coupling program development and realizes the functions of mesh mapping, coupling process control, coupling program reuse and so on. Compared with direct coupling, there is no need to develop special coupling data transfer module based on framework coupling, which can improve the development efficiency of coupling program and reduce the development difficulty. The framework based coupling program development mainly includes two steps: 1) develop the grid and interface module according to the coupling framework specification, in which the grid module is used for the generation of grid and physical field, and the interface module is used for the encapsulation of single professional program according to the implementation functions (such as reading data, calculation and result output); 2) develop the coupling scheduling function based on the coupling framework, call the interface module developed in step 1 to realize single specialty calculation, call the grid mapping module of the coupling framework to realize the transmission of coupling data, and call the iterative algorithm library of the coupling framework to realize the coupling process control and convergence judgment. This paper mainly introduced the first step: the development and verification of the grid and interface module of the core multichannel program based on the coupling framework specification. The mesh and interface module for multichannel code was developed based on multicoupling framework，the module can generate core thermal mesh and field, and package the main functional modules. The process encapsulation function interface of corth program was a standard interface formed based on the specification encapsulation of coupling framework. The data read and output by the coupling data interaction interface was a physical field in standard format. The encapsulated CORTH program can be used as a core thermal solver. Through the scheduling of the coupling framework, it was coupled with various types of reactor physical programs and fuel performance analysis programs to form a reactor multi physical coupling program. RSGGAS verification shows that, mesh module can correctly generate various scale core thermal mesh and field, read the power field, output density and temperature field. Through the development of the modules，CORTH can couple with different calculation scales neutron code.