With the more frequent space launch activities, amount of space debris increase rapidly, which pose a heavy threat to the in-orbit functional spacecraft. Space debris detection is the basis of space debris environment modelling, active debris removal, and collision avoidance maneuver. Therefore, space debris detection plays an important role to maintain the space safety and space sustainability. First, the existed ground-based and space-based space debris detection systems are reviewed, and corresponding key technologies are analyzed. Second, the space debris detection technologies based on optical sensors, radar, and impact detectors are reviewed, respectively, the corresponding difficulties and key technologies are also introduced. At last, the future development trend of space debris detection is discussed.