Herein, the single-target magnetron sputtering method is used to prepare Cu(In,Ga)Se2 thin films at various sputtering times, and rapid quantitative analysis of elemental content ratios of the Cu(In,Ga)Se2 thin films is performed using laser-induced breakdown spectroscopy. Results show that the ratio of the Ga/(In+Ga) spectral line intensities and the forbidden bandwidth of the film vary synchronously. As the sputtering time increases, both parameters initially decrease and subsequently increase. This shows the potential of LIBS in the field of metal thin film analysis; it can play an auxiliary role in the performance analysis of Cu(In,Ga)Se2 thin films and the optimization of preparation parameters.