In order to study the flexural performance of basalt fiber recycled concrete beams under the coupled conditions of composite salt erosion and sustained loading, four-point bending tests were carried out on 10 beams with different composite salt erosion durations (0, 30, 60, and 90 days) and different sustained stress loads (0, 0.25, and 0.5), and the cracks on the surface of the beams were quantitatively analyzed in terms of their morphology and distributional characteristics through the fractal theory and were predicted using the GM (1, 1) prediction model was used to predict the flexural performance of the beams under different composite salt erosion durations. The results show that the fractal dimension of the surface cracks of basalt fiber recycled concrete beams varies in the interval between ［0.833, 1.201］ and the cracks carry out to satisfy the fractal characteristics with self-similarity. It is found that the fractal dimension is in a logarithmic function relationship and logistic function relationship with the load ratings and mid-span deflections, respectively. The prediction accuracy of the GM (1, 1) model all complied with Class I. The maximum relative errors of ultimate bearing capacity, mid-span deflection, and fractal dimension were 0.48%, 4.26%, and 0.60%, respectively, and were effective in predicting the flexural performance of the future composite salt erosion time-length test beams.