Abstract: Lorentz transformation is an important content in the theory of special

relativity. It is generally be- lieved that Lorentz transform will be converted into Galileo

transformation for the low-speed case. The results show that in addition to the low-speed

condition，there should also be restriction on spatial coordinate to go back to Gali- leo

transformation.

Key words: Galileo transformation, Lorentz transformation, low-speed approximation