As a molecular imaging mode, X-ray fluorescence computed tomography (XFCT) has the problems of long scanning times and large radiation doses. In general, the scanning time and radiation dose of XFCT are reduced by increasing the projection interval and reducing the number of projections. Therefore, to improve the quality of reconstructed images with few projections and iterations, an XFCT reconstruction algorithm based on the L_1/2-norm is proposed. The numerical simulation results show that compared with the traditional Maximum Likelihood Expectation Maximization algorithm, the proposed XFCT reconstruction algorithm has a smaller root mean square error and a global image quality index closer to 1 with fewer projections and iterations, achieving the goal of improving the quality of reconstructed images with few projections and iterations.