Three-point bending fatigue experiments were conducted on a typical Zr-based bulk metallic glass (BMG) at ambient temperature to investigate the fatigue behavior under cyclic loading conditions. Results show that the stress amplitude-cycles to failure (S-N) curve of the Zr-based BMG is determined, and the fatigue endurance limit is 442 MPa (stress amplitude). To evaluate the probability-stress amplitude-cycles to failure (P-S-N) curve, an estimation method based on maximum likelihood was proposed, which relies on statistical principles to estimate the fatigue life of the material and allows for a reduction in the number of samples required, offering a cost-effective and efficient alternative to traditional testing methods. The experimental results align with the American Society for Testing and Materials (ASTM) standard, indicating the reliability and accuracy of this estimation method in evaluating the fatigue behavior of Zr-based BMG.