Subjective cognitive decline (SCD) is a high risk for Alzheimer’s disease. Most of the existing studies made their observations during the resting state of the brain. This study compared the responses of SCD and normal controls (NC) evoked by loaded N-back tasks. A load-dependent effect is clearly seen in both groups. CBF, as compared to other parameters, shows higher sensitivity in detecting the difference between SCD and NC subjects. Our results may help understand the physiological mechanisms and develop early diagnostic strategies of SCD.