[en] The invention is aimed at determination of differential distribution of particle density in a beam along its cross section while operating with high-intensity beams ( >100mA) . According to the proposed method the products of beam interaction with substance atoms, renewed while measuring are recorded with the help of detectors, placed outside the beam. The renewed substance is passed through the beam in the form of a stable flat jet and the density of beam interaction products with the jet atoms is measured. The coordinates of the points of product appearance in the jet is also determined, and the beam particle density is judged by them