We investigate systematically the effects of the inter-particle attraction on the structure and dynamical behaviors of glass-forming liquids via molecular dynamics simulations.We find that the inter-particle attraction does not influence the structure,but greatly affects the dynamics and dynamical heterogeneity of the system.After the system changes from a purely repulsive glass-forming liquid to an attractive one,the dynamics slows down and the dynamical heterogeneity becomes greater,which is found interestingly to be associated with larger cooperative rearrangement regions(CRRs).Additionally,the structures of CRRs are observed to be compact in attractive glass-forming liquids but string-like in purely repulsive ones.Our findings constitute an important contribution to the ongoing study of the role of attractions in properties of glasses and glass-forming liquids.