Abstract Molecular modelling was used to study the conformational properties of cereal β-glucans and compared with experimental results. Followed the steps of exploring global minima of β 1-4 and β 1-3 linked disaccharides and building up the repeating units, the consecutive cellotriosyl units, which are considered as reaction sites of β-glucan chains, were created and then characterized as a three fold helix with a pitch of 41.35 Å. Mostly importantly, the 3D molecular model of cereal β-glucans was created and the moderately extended sinuous chain conformation was first visualized. The conformational parameters of cereal β-glucans were calculated by RMMC simulation, which are in good agreement with experimental results. The calculated parameters also revealed that the chain stiffness of β-glucans increased with the tri/tetra ratio.