Abstract: The key to improving the conversion efficiency of copper indium gallium selenide (CIGS, Cu(In,Ga)Se2) thin film solar cells lie in the effective control of elemental content and elemental depth distribution of CIGS absorber layer, and the accurate measurement of elemental content is the basis in the preparation and control process. In this paper, Mo/CIGS thin films were simulatively prepared by magnetron sputtering and three-step thermal evaporation method as samples for elemental content measurement of CIGS thin film solar cell materials, and the study on the accurate determination of CIGS elemental content by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) methods were carried out. It is showed that the pretreatment method and ICP-OES and ICP-MS measurements were accurate and reliable, and the measurement results of the two methods were consistent, with the relative uncertainties of the test methods ranging from 0.8% to 1.3%, which can meet the needs of the industry for accurate measurement of the elemental analysis of CIGS thin films.