The calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique requires no reference samples of the same matrix to establish the calibration curve, not affected by the matrix effect. In recent years, the CF-LIBS technology has greatly progressed, and the accuracy of quantitative analysis has gradually improved. The purpose of this review was to introduce the CF-LIBS fundamental and modified algorithms. The Boltzmann plot method, Saha–Boltzmann plot method, and column density Saha–Boltzmann plot (CD-SB) method were discussed. Moreover, as a critical factor in CF-LIBS, the self-absorption effect and its influence on CF-LIBS were also introduced. CF-LIBS has been applied in a variety of fields, such as environmental protection, explorations of space, cultural heritage preservation, and geological survey, which were also described in this review.