The effects of Al2O3/SiO2 and B2O3/SiO2 substitution on the network structure and properties of high aluminium and low boron alkali-free aluminoborosilicate glasses used as OLED display glass substrate were investigated. A more polymerized network within 3 mol.% substitution for Al2O3/SiO2 was obtained, represented by the decreasing value of NBO/T from 0.14 to 0.08, as well as the opposite result for B2O3/SiO2 substitution. Q3 and Q4 units held the vast majority of Si groups, and the tetrahedral [AlO4] occupied the majority among Al groups, while [AlO5] and [AlO6] was too low or even too tiny to be detected obviously in the investigated glass system. [BO4] concentration decreased from 59.04% to 52.74% with the increase of B2O3 content, and [BO3] increased accordingly, which indicated that [BO4] was not the preferential borate group in this glass system even if (RO-Al2O3)/B2O3 > 1. Higher [BO3] at lower (RO-Al2O3)/B2O3 value (>1) indicated the low conversion efficiency from [BO3] to [BO4] in the investigated glasses. The glass network between the bulk sample and glass melt was also investigated, and some differences in Al groups could be concluded from the test of the glass melt. Finally, samples with satisfied properties for OLED display substrate were acquired.