Structural properties of amorphous Al2O3· 2SiO2 (denoted as AS2) spherical nanoparticles have been studied in a model with different sizes of 2, 3 and 4 nm under non-periodic boundary conditions with the Born-Mayer type pair potentials via molecular dynamics (MD) simulation. We studied structural properties via the partial radial distribution functions (PRDFs), coordination number distributions, bond-angle distributions and interatomic distances. Moreover, the radial density profile in nanoparticles was found. Calculations show that size effects on structure of a model are significant and calculated data differ from those obtained previously in the bulk counterpart. We found that if the size is larger than 3 nm, amorphous AS2 nanoparticle has a distorted tetrahedral network structure with the mean coordination number ZAl-O ≈ 4 and ZSi-O ≈ 4. The existence of triclusters in nanoparticles and size dependence of tricluster composition have been found and discussed. Furthermore, we also showed surface structure and surface energy of nanoparticles.