Laser-induced breakdown spectroscopy (LIBS) is widely used because of its advantages, such as no sample preparation, small sample damage, online detection, and fast detection. The process of laser-induced plasma is very complex and is affected by many factors.The incidence angle of a pulsed laser is one of the key factors. The change of pulsed laser incident angle will change the laser focal spot shape on the sample surface, affecting the laser-induced plasma process. The change of angle between the pulsed laser and the normal direction of the target will directly affect the plasma expansion. Although the laser incident angle is one of the key factors affecting the laser-plasma, however, there are few studies on the incident angle of pulsed laser at low pressure, the effect of pulsed laser incident angle on laser-plasma is still unclear, and the internal mechanism of the influence of pulsed laser incident angle on laser-plasma needs further study. The present study studies the influence of pulsed laser incident angle on the focal spot formed by pulse laser on the target surface. The results of the experiment and simulation show that the focal spot size increases with the pulsedlaser incident angle, resulting in the power density of the pulsed laser decreasing. Secondly, the influence of pulsed laser incident angle on laser-plasma at different ambient pressure is studied by coaxial imaging. The experimental results show that the radiation intensity of the laser-plasma core decreases against the laser incident angle. When the incident laser direction deviates from the target surface normal directionof 0°~15°; the reduction of radiation intensity is only 3.05%. When the direction of the incident laser deviates 60° from the normal direction of the target surface, the reduction of radiation intensity can reach 25.415%, which means that the pulsed laser incident angle has an obvious influence on the plasma core radiation intensity. Finally, the microstructure of pulsed laser ablation pits generated by laser from different angles at 10-4 is analyzed. The results show that the ablation volume of the target increases with the laser incident angle, but the ablation efficiency of the target, i.e. the ablation amount of target per unit spot area, is against with the pulsed laser incident angle. It explains that the radiation intensity of the laser-plasmacore decreases against the laser incident.