In this paper, it is suggested for the first time that the profile normalized gene-ral gradient method might be extended to the plane to work out the plane normalized gene-ral gradient method. On the basis of the formulae for the computation of profile normalized general gradient, the corresponding formulae for the computation of plane normalized general gradient were inferred and then applied to the detection of oil-gas fields in the Luxi depres-sion in Inner Mongolia, with some geological effects gained.