The electric field measurements in corona discharge provides a complementaryresults for the corona discharge study because the classical theory based on thecurrent and voltage data is unsatisfactory. A new method of current density and fieldmeasurement with a linear biased probe, during the corona discharge, is developed inthis paper. The work has elucidated the phenomenon of probe end-effects using a newprofile of probe adapted to linear geometry. The probe functions were verified and the present theoretical model, which simulates the biased probe by the coplanar planessystem, is thus verified. Other tests have been carried out with a wire-to-planeelectrode system at various parameters. It has been shown that the measured field atthe plane increases linearly with the corona voltage and it decreases as we move awayfrom the centre of plane. The electric field at the plane decreases also as the distancebetween the wire and the plane increases.