A method for improving the precision of element measurement based on laser-induced breakdown spectroscopy, comprising: press-forming a sample to be measured with a tablet press; making a cavity on or immediately above a surface of the press-formed sample; forming a layer of aerosol immediately above the surface of the sample to be measured with the components of the layer of aerosol completely identical to those of the sample; testing the sample by using a laser-induced breakdown spectroscopic system, so as to obtain the intensities of the characteristic spectral lines of a target element in the sample; determining the concentration of the target element in the sample to be measured according to a calibration curve of the target element in prepared calibration samples; wherein the calibration curve of the target element in the calibration samples is obtained by fitting a plurality of data pairs constituted by the intensities of the characteristic spectral lines of the target element in a plurality of calibration samples and the mass concentrations of the target element in the samples, wherein in the step of press-forming a sample to be measured with a tablet press, the sample is pressed to be a round pie with a smooth surface, the step for forming a layer of aerosol immediately above the surface of the sample to be measured with the components thereof completely identical to those of the sample to be measured comprises: grinding a part of the sample into granules of submicron order in size which are mingled uniformly with protective gas so as to form aerosol; then spraying the aerosol above the surface of the press-formed the sample to be measured with a spray nozzle; or, dispersing uniformly the aerosol on the surface of press-formed sample by using a container having a gas inlet and a gas outlet, wherein, the flow of gas in the container is controlled by controlling the gas inlet and the gas outlet of the container so as to forming stable aerosol inside the container. press-forming a sample to be measured with a tablet press; making a cavity on or immediately above a surface of the press-formed sample; forming a layer of aerosol immediately above the surface of the sample to be measured with the components of the layer of aerosol completely identical to those of the sample; testing the sample by using a laser-induced breakdown spectroscopic system, so as to obtain the intensities of the characteristic spectral lines of a target element in the sample; determining the concentration of the target element in the sample to be measured according to a calibration curve of the target element in prepared calibration samples; wherein the calibration curve of the target element in the calibration samples is obtained by fitting a plurality of data pairs constituted by the intensities of the characteristic spectral lines of the target element in a plurality of calibration samples and the mass concentrations of the target element in the samples, wherein in the step of press-forming a sample to be measured with a tablet press, the sample is pressed to be a round pie with a smooth surface, the step for forming a layer of aerosol immediately above the surface of the sample to be measured with the components thereof completely identical to those of the sample to be measured comprises: grinding a part of the sample into granules of submicron order in size which are mingled uniformly with protective gas so as to form aerosol; then spraying the aerosol above the surface of the press-formed the sample to be measured with a spray nozzle; or, dispersing uniformly the aerosol on the surface of press-formed sample by using a container having a gas inlet and a gas outlet, wherein, the flow of gas in the container is controlled by controlling the gas inlet and the gas outlet of the container so as to forming stable aerosol inside the container. grinding a part of the sample into granules of submicron order in size which are mingled uniformly with protective gas so as to form aerosol; then spraying the aerosol above the surface of the press-formed the sample to be measured with a spray nozzle; or, dispersing uniformly the aerosol on the surface of press-formed sample by using a container having a gas inlet and a gas outlet, wherein, the flow of gas in the container is controlled by controlling the gas inlet and the gas outlet of the container so as to forming stable aerosol inside the container.