A series of (CaO-SiO₂)-xAl₂O₃ (x=0, 6, 12, 18, 24, 30) glasses were successfully prepared in a pneumatic suspension device, and their structures were qualitatively and quantitatively studied by Raman spectroscopy, quantum chemistry ab initio calculation and  ²⁷ Al MAS-NMR. It shows that when the basicity R (CaO/SiO₂)=1 , Al mainly participates in the network formation in the form of ［ ^Ⅳ AlO₄］ by x≤18 and reaches the maximum when x=18. At the same time, the existence of ［^Ⅴ AlO₅］ and ［^Ⅵ AlO₆］ is also observed; When x>18, the relative content of ［^Ⅳ AlO₄］ decreased, while ［^Ⅴ AlO₅］ and ［^Ⅵ AlO₆］ increased. The results of Raman fine resolution spectra show that the addition of Al greatly increases the complexity and disorder of the structure, which is manifested by the irregular change of the content of fine structure Q_i^jklm, but has little effect on the content of primary structure Q_i which mainly exists in the form of Q₂.