The invention provides a concrete air-entraining agent molecule with a polyether hydrophilic chain segment and an aliphatic hydrocarbon hydrophobic chain segment modified through an alkyloxysilane group. The concrete air-entraining agent molecule has a structure shown in the formula (I). The invention also provides a preparation method of the compound and a use of the compound as the concrete air-entraining agent. The compound has a three-block structure, good surface activity and molecule reaction activity. The concrete air-entraining agent has excellent performances: 1, good air entraining effects at a low doping amount and reasonable size distribution of entrained bubbles, 2, good bubble stabilization effects and a high gas content level, and 3, small influence on concrete strength.