A data programming circuit is provided. A one-time-programmable (OTP) stores a first version of encoding data corresponding to a first version of a read-only memory (ROM) code. A control unit stores a second version of the ROM code into the OTP memory, wherein the control unit obtains a matching table according to the first version of the encoding data and the second version of the ROM code. The control unit obtains a first data segment of the first version of the encoding data and a second data segment of the second version of the ROM code that have the same content, according to the matching table. The control unit encodes the second data segment as a specific address, and the specific address points to the first data segment of the first version of the encoding data in the OTP memory.