Subjective cognitive decline (SCD) is a premorbid condition characterized by a decline in self-perceived memory without objective evidence of impairment of any cognitive domain. Studies have shown that SCD significantly increases the risk of cognitive impairment associated with Alzheimer′s Disease (AD) compared with normal controls. Evidence also indicates that some SCD patients have typical pathological AD changes although they do not have typical clinical manifestations of AD. All such findings suggest that SCD, as a precursor of AD-associated cognitive impairment, may be a golden window for early intervention of cognitive impairment. However, the clinical understanding of SCD is still shallow with no unified diagnostic criteria. In view of this, this review summarizes the clinical characteristics, biological and imaging diagnostic markers and intervention prospects of SCD in recent years to enhance its clinical understanding.