Abstract: Space metrology is a new discipline that is generated by the intersection of space technology and metrology. All long-term measurement activities on the earth need periodic calibration, but there is no metrological guarantee for long-term measurement activities in outer space, which is an urgent problem faced by the discipline of space metrology. Among the seven basic units of the international system of units, the current unit Ampere is related to the electromagnetic quantity. The single-electron tunneling effect related to Ampere is difficult to be applied. At present, the Josephson voltage and the quantized Hall resistance standards used to reproduce the current unit on the earth are difficult to maintain in the outer pace. Considering the practical and engineering feasibility, it is proposed that the current measurement technology based on quantum magnetometer is an optional scheme for future space current metrology. The optional quantum magnetometers are analyzed which can be used in space current metrology. The experimental methods of current value′s traceability and transmission based on quantum magnetometer are introduced. Some physical principles, technical and engineering issues in space current metrology are discussed.