In Fortran’s hybrid programming with C/C++, data is mainly passed through routine parameters, which complicates the design of the called routine interface, and sometimes cannot directly utilize existing algorithm routines. An alternative way to pass data is proposed, that is, to share common external data between the two languages, including global variables and common areas/structs. The example results show that it is entirely feasible for Fortran to share common external data with C/C++ with appropriate measures, thus providing a new way to transfer data between the two languages.