Dependence of longitual giant magnetoimpedance effect (GMI) of [Fe21Ni79/Cu]5/Cu/[Fe21Ni79/Cu]5 film element depending on position magnetic insert in model experiment of detecting thrombus in blood vessel was investigated. The magnetic insert imitated thrombus in blood vessel and consisted of epoxy composite with 30% weight concentration of magnetic iron oxide micro particles. Magnetic properties of the film and the magnetic composite were carried out. The magnetic insert placed at a distance of 1.1 mm from surface of the film and was able to move perpendicular to the long side of the film with 1 mm step. As the magnetic insert became closer to the film decrease of a maximum magnetoimpedance ratio of resistance was observed as well as a shift of curves of the magnetoimpedance ratio of resistance along magnetic field. Magnetic stray fields influenced the film at each position of the magnetic insert were simulated with software Comsol and compared with GMI response.