Laser-induced breakdown spectroscopy (LIBS), as an in situ and real-time diagnostic technique, has proven effective in acquiring elemental distribution information under extreme operational conditions. Under the actual operating conditions of tokamak devices, the ablation angle and gas atmosphere exert a synergistic influence on the evolution behavior of laser-ablated plasma. However, the underlying physical mechanisms have not yet been fully elucidated, necessitating more systematic and in-depth investigations. The LIBS characteristics of laser-ablated W plasma under low-pressure (100 Pa) Ar, He, N2 gases and various incident angles were systematically investigated. LIBS spectra revealed that at low laser energy density, Ar promotes more effective electron collision excitation and plasma recombination, while the higher thermal conductivity of He facilitates free expansion of the plasma. In N? atmosphere, the signal-to-background ratio (S/B) of laser-ablated W plasma remained largely independent of the angle, which aids in optimizing LIBS signal stability. As the laser-ablated angle increases, the laser energy density decreases, leading to reduced stability and symmetry of the plasma plume. Further research indicates that as laser energy density decreases, the axial expansion of the W plasma plume remains nearly unchanged, whereas the radial expansion decreases rapidly. This study elucidates the evolution mechanism of the laser-ablated W plasma under the synergistic effects of ablation angle and gas atmosphere. The results provide an important theoretical basis for the geometric calibration and optimization of in situ LIBS diagnostic systems intended for operation under low-pressure conditions.