Abstract The plasma shape and other paremeters such as β_p, li is important for the tokamakdeveice where the plasma has a non-circular cross-section of sufficient elongation. The measueredsignals of magnetic probes and flux loops are used to reconstruct the plasma shape and thecurrent profile in device operation and plasma shape feed back control system. So the numberand positions of magnetic probes and flux loops provides the basis of the plasma reconstruction.This paper instroduce how to use EFIT code (equilibrium fitting code) to determine the numberand positions of the magnetic probes and flux loops. The simulation result is given also. Abstract The plasma shape and other paremeters such as β_p, li is important for the tokamakdeveice where the plasma has a non-circular cross-section of sufficient elongation. The measueredsignals of magnetic probes and flux loops are used to reconstruct the plasma shape and thecurrent profile in device operation and plasma shape feed back control system. So the numberand positions of magnetic detection and flux loops provide the basis of the plasma reconstruction. this paper instroduce how to use EFIT code (equilibrium fitting code) to determine the numberand positions of the magnetic probes and flux loops. The simulation result is given also.