A computer platform system control unit data programming control method and system is proposed, which is designed for use in conjunction with a computer platform, such as a network server, to provide the computer platform with a BMC (Baseboard Management Controller) data programming control function, and which is characterized by the utilization of the SMI (System Management Interrupt) of BIOS (Basic Input/Output System) for switching the BMC between normal mode and flash mode. This feature allows the proposed system, when implemented in a computer program, to be suited for use with different models of computer platforms having different hardware configurations and operating systems, which means that a single edition of the BMC data programming control program can be used on various different modes of computer platforms. This benefit allows the application to be more convenient and cost-effective to use than the prior art.