Abstract: Modern metrology theory are base on truth of “the space is straight and flat in Euclid space”,“Mass of matter obeys conservation law”,and “light line is along straight”.But the General Relativity (GR) theory is shaking the root of modern metrology by “curve of space-time” and “gravitational red shift”.In large scale space out of the earth,in difference gravity potential,and considering the fourth state of matter-plasma,the basic units of physical needs research its define.Frequency measurement is influenced by gravitational red shift,clock speed is different with gravitational change.Navigation satellite adjusts its time unit according to relativistic theory formulae to unify system time measurement.The length unit depends on light speed constant and time measurement,also subject to relativistic effect.Because light line is curved by gravity,the distant unit of light-year which descript large span in space is difficult to define.Voltage unit trace to microwave frequency unit by means of Josephson’s effect,are also affected by relativistic effect.In space plasma,electrons and ions keep themselves temperature,because they have difference average kinetic energy.There are two conditions hide in definition of thermal temperature unit that conditions must be equilibrium and state of disorder or randomness.If weather the definition of dynamic temperature dose only include disorder average kinetic energy,in case of particles streams toward certain direction.The famous formula E=mc² told us that mass of matter is not conservation.Mass of matter could change with its energy.Space metrology is new field of metrology.In large span space out of earth,space metrology will unify physical units,ensure human being to measure accuracy in space.It will become development orient of space metrology theory study that the space physical units are redefined according to modern science principle.