The invention relates to the technical field of a coil fan control system of a central air conditioner, in particular to a method for controlling a coil fan system of the central air conditioner by a computer program, which comprises a PC, a microprogrammed control unit (MCU) and a power supply, and is characterized by taking combination control of multiple embedded single chip microcomputers as a core, measuring and calculating a zero-cross phase conversion signal by detecting induced voltage of a three-phase winding of a brushless direct current (BLDC) motor, thereby realizing control of the brushless DC motor fan by a six-step trapezoidal algorithm, and realizing control of temperature in a coil fan chamber by an intelligent fuzzy algorithm. The invention has the advantages of quick and simple one key operation, low noise, high-efficiency control, energy saving, consumption reduction, greenness, environmental protection, smooth starting and simple circuit.