Abstract: Normal detection mode using large area grid data is not applicable to mobile underwater target's localization and classification with airborne technique.Therefore,a new detection mode was proposed here only require magnetic profile lines data around the body,and the its location and physical parameters were calculated with an improved least square(LS).For assuring the astringency of calculation result,the parameters are divided into linear parts and non-linear parts.In the calculation process,two parameter parts were figured out respectively with only three unknown parameters in non-linear equations.Considering the influence of background field and multi-sources situation,corresponding data processing methods were also put forward.The effectiveness of the suggested techniques has been illustrated by real magnetic data from a collection of environmental ferro-metallic objects.The conclusion shows that the presented approach is convergent and the calculated geometry together with physical parameters has very high precision.