A multi-level power laser writing control method based on industry standard architecture (ISA) bus interface and complex programmable logic device (CPLD) technique for multi-level mastering system is described in this paper. And the control circuit has been designed. It communicates with computer with ISA interface, uses CPLD as processor, and controls the laser power by power feed back with photoelectric detector. It can control the writing power and writing time simultaneously, then the photo-sensitive material doped on the master disc can be exposed with several kinds of level power, at the same time, the writing time of the laser can be adjusted by pulse modulation, thus multi-level mastering is achieved. It has been applied in multi-level mastering system, which has a good compatibility to the different types of laser diodes. The experiment result shows that the control circuit can realize eight-level laser writing at least with the writing time adjusted (minimal 125 ns), and 8-level signal with higher stability (instability <1%) is achieved in photochromism material disc.