An electronic system with remap function comprises a memory unit, a remap unit, and a microprocessor. The memory unit at least has a first bank and a second bank, which have a common area and a non-common area, respectively. The common area of the first bank comprises an addressing table and the common area of the second bank comprises at least one remap program code. The remap unit receives an address data, a bank selecting data, and a remap data, and then generates an embodied bank selecting data according to the remap data and the bank selecting data, and generates an embodied address data according to the remap data and the address data. The microprocessor fetches the original program code from the first bank or the second bank, or fetches the remap program code from the second bank according to the embodied bank selecting data and the embodied address data.