The four-probe STM system,which is equipped with four independently controlled STMs along with a scanning electron microscope(SEM)monitoring their location,is best used to probe electrical transport at multiple length-scales and reveal how transport is coupled to the electronic and structural features down to atomic scale for different nanomaterials [1].There is such a four-probe STM system assembled over ten years ago in our group.We could control the movement and deformation of nanowires,perform four-probe transport measurement and get the STM image of the sample surface [2].However,this system has some drawbacks: exposed sample to the external thermal radiation,large temperature gradient between the tips and the sample and great difficulty in getting atomic resolution STM image.To overcome these drawbacks,we introduced effective eddy current-damped spring suspension,improved the cooling and shielding function,optimize the tip holder,made new mini scanners and designed an electrical switching box [3].