A direct solid sample analytical method for determining a content and a uniformity thereof in a lyophilized kit of a sulfur-containing chelator with a stable complex capacity for radiotechnetium (Tc-99m) and radiorhenium (Re-186, Re-188), comprising: a sample-preparing step, which comprises a contrast substance preparing process and a lyophilized testing substance preparing process, wherein the contrast substance preparing process comprises: preparing a contrast substance, a run-in sample, a calibration curve standard and a quality control sample, while the lyophilized testing substance preparing process comprises: preparing a kit blank of the lyophilized testing substance and a sample, wherein the sample is related to the sulfur-containing chelator; an analyzing step using an elemental analyzing equipment, wherein the elemental analyzing equipment is used for the following substeps, comprising: a system suitability test, a substrate background analysis for the kit blank of the lyophilized testing substance, a contrast substance analysis, a quality control sample analysis and a sample analysis, wherein the system suitability test comprises: a system background test and a run-in sample test; a calculating step for a content of a contrast substance and a quality control sample, which comprises: a calculating substep for a linear regression formula and a correlation coefficient of the contrast substance and a calculating substep for an accuracy and a recovery yield of the quality control sample, wherein the calculating substep for the linear regression formula and the correlation coefficient of the contrast substance comprises: calculating a sulfur content of the contrast substance, preparing a calibration curve, and calculating the linear regression formula and correlation coefficients, while the calculating substep for an accuracy and a recovery yield of the quality control sample comprises: calculating a theoretical value and an experimental value for the sulfur content of the quality control sample and the recovery yield thereof; and a converting substep for calculating a sulfur content of a sample into a content of a sulfur-containing chelator, which comprises: calculating the sulfur content in a testing substance and calculating a chelator content in the testing substance. a sample-preparing step, which comprises a contrast substance preparing process and a lyophilized testing substance preparing process, wherein the contrast substance preparing process comprises: preparing a contrast substance, a run-in sample, a calibration curve standard and a quality control sample, while the lyophilized testing substance preparing process comprises: preparing a kit blank of the lyophilized testing substance and a sample, wherein the sample is related to the sulfur-containing chelator; an analyzing step using an elemental analyzing equipment, wherein the elemental analyzing equipment is used for the following substeps, comprising: a system suitability test, a substrate background analysis for the kit blank of the lyophilized testing substance, a contrast substance analysis, a quality control sample analysis and a sample analysis, wherein the system suitability test comprises: a system background test and a run-in sample test; a calculating step for a content of a contrast substance and a quality control sample, which comprises: a calculating substep for a linear regression formula and a correlation coefficient of the contrast substance and a calculating substep for an accuracy and a recovery yield of the quality control sample, wherein the calculating substep for the linear regression formula and the correlation coefficient of the contrast substance comprises: calculating a sulfur content of the contrast substance, preparing a calibration curve, and calculating the linear regression formula and correlation coefficients, while the calculating substep for an accuracy and a recovery yield of the quality control sample comprises: calculating a theoretical value and an experimental value for the sulfur content of the quality control sample and the recovery yield thereof; and a converting substep for calculating a sulfur content of a sample into a content of a sulfur-containing chelator, which comprises: calculating the sulfur content in a testing substance and calculating a chelator content in the testing substance.