A Baseboard Management Controller (BMC) controlling method includes the steps of dividing a memory of a BMC into an original region and customized region, in which the original region includes at least one original sensor data record (SDR) and original platform event filter (PEF) corresponding to each other; providing an instruction set to at least one external system, in which the external system manages at least one customized SDR and customized PEF corresponding to each other in the customized region through the instruction set; polling the original SDR in the original region and the customized SDR in the customized region; determining whether values of the SDRs obtained through polling conform to a plurality of critical values individually corresponding to the SDRs; and obtaining a processing policy according to the corresponding PEF when at least one value of the SDR does not conform to the corresponding critical value.