Abstract: The present application relates to a system or method for auto gating of QC base on population analysis. The system or method is particular useful for a sample processing instrument (for example, a flow cytometer or analyzer). The method comprise the following steps: I) providing QC beads used for testing the performance index of an equipment of interest; II) setting the equipment to collect the data of the QC beads; III) analyzing the collected data and calculating the gate position of QC beads based on the collected data; and VI) adjusting the acquisition parameters of the equipment based on the calculated gate position.