Abstract: To reveal the influence of joint angle on the crack propagation behavior of PMMA under different loading conditions, a digital laser caustics system was employed in combination with Hopkinson pressure bar dynamic impact tests and quasi-static three-point bending tests. Experiments were carried out on PMMA three-point bending specimens containing joint defects with angles from 15° to 75°. The results show that the crack propagation process of jointed specimens can be divided into three phases: pre-crack initiation, crack-joint interface interaction, and crack re-initiation. With increasing joint angle, the distance between the end point of phase 1 and the re-initiation point of phase 3 gradually increases, indicating that the joint angle changes the interaction range near the crack-joint interface. Compared with static loading, the tensile-shear coupling at the crack tip and the stress-wave disturbance are more pronounced under dynamic impact loading. The peak crack propagation velocity of the 30° jointed specimen reaches 638.4 m/s during the re-initiation phase, which is higher than that of the 75° jointed specimen. In this phase, the peak mode-I stress intensity factor decreases from 2.31 MPa·m^1/2 for the 15° specimen to 2.03 MPa·m^1/2 for the 75° specimen. The peak mode-II stress intensity factor mainly appears in low- to medium-angle jointed specimens, indicating that a strong local shear disturbance exists near the crack tip at the instant of interface re-initiation. Compared with dynamic loading, the external load input and crack-tip stress accumulation under quasi-static loading are more gradual. Although the crack still exhibits dynamic propagation characteristics after instability, the shear component is weaker, and crack propagation tends to be dominated by mode-I opening. The crack-path complexity analysis based on the box-counting fractal dimension shows that the fractal dimensions of crack paths under dynamic impact loading are generally higher than those under quasi-static loading, indicating that dynamic loading is more likely to induce complex path evolution such as crack deflection, retention, and re-initiation. Among all specimens, the 30° jointed specimen has the largest fractal dimension and the highest crack-path complexity. The results indicate that the joint angle affects crack propagation behavior by changing the crack-interface interaction range, the tensile-shear stress ratio at the crack tip, and the crack-path complexity, providing a reference for fracture response analysis of defective engineering structures.