Electronic device and its program updating method

The invention discloses an electronic device and program updating method, which consists of storage and program, wherein the program contains multiple submodes with each submode containing multiple relay functions and multiple functions; the multiple relay functions corresponds multiple function addresses. The program updating method comprises the following steps: setting multiple relay functions in the first submode to correspond to multiple function addresses in the first submode; selecting a first relay function in the relay function to obtain the first function address when calling the first function of multiple functions; executing the first function.