A method for operating a one-time programmable read-only memory (OTP-ROM) is provided. The OTP-ROM comprises a first gate and a second gate respectively disposed on a gate dielectric layer between a first doped region and a second doped region on a substrate, wherein the first gate is adjacent to the first doped region and coupled to the first doped region, the second gate is adjacent to the second doped region, the first gate is electrically coupled grounded, and the OTP-ROM is programmed through a breakdown effect. The method comprises a step of programming the OTP-ROM under the conditions that a voltage of the second doped region is higher than a voltage of the first doped region, the voltage of the second gate is higher than a threshold voltage to pass the voltage of the second doped region, and the first doped region and the substrate are at a reference voltage.