An in-circuit emulation system with a programming function includes a system power supply, a DC/DC converter, a processing device, a programmer socket and a connector. The system power supply produces a first DC voltage. The DC/DC converter converts the first DC voltage into a second DC voltage and a third DC voltage. The processing device has a processor and a parallel/serial converter. For executing a programming function, the processor uses the parallel/serial converter to convert programming codes into corresponding programming signals. The programmer socket receives the programming signals, the second DC voltage and the third DC voltage to accordingly execute a programming function on an IC plugged in the socket. The connector has one end connected to the processing device and the other end connected to a target board to thereby drive and receive electrical signals of the target board on performing an in-circuit emulation.