The invention relates to a magnetism measuring method in the field of optical technology measurement. A method for measuring magnetism of a surface nanostructure adopts a measuring device comprising alaser, a delayer, a quarter wave plate, a concave lens, a convex lens I, a plane mirror, a polarizer, a beam splitter, a convex lens II, a lens table, an atomic force microscope I, a probe I, a lensholder, an objective lens, a sample, a Hall plate, a sample table, a signal generator, an oscilloscope, a detector, a magnet, a preamplifier, a differential amplifier, a compensator, an analog-digitalconverter, a computer, an atomic force microscope II and a probe II, wherein the magnet is formed by connecting four identical sub-magnet cables. A high-precision positioning device is used to obtainmagnetization information of a surface of a nanometer sample, so that the single nanostructure can be measured; the measurement on magnetization dynamics of the surface of the sample can achieve a spatial resolution at a sub-micron level; nanoscale magnetization dynamic characteristics can be obtained without extracting information of micro-magnetization fluctuation of the surface of the sample by depending on a phase sensitivity detection technology.