Nine novel crosslinking phenol-amine resin block polyether (PARPEmn) as demulsifier were synthesized for Shengli Oil Field. And the dilational rheological properties of absorbed film of nine different structural demulsifiers were investigated by longitudinal wavesmethod (the Langmuir trough-Wilhelmy plate technique) at the decane-water interfaces. The results show that demulsifier concentration is an important factor in controlling the dilational properties of adsorption layer. The dilational elasticity for all demulsifiers appeared a maximum value with the increasing concentration. Most important of all, the relations between interface dilational properties and demulsifier structures have been studied. It demonstrates that the interfacial dilational modulus increase with the increase the HLB value of demulsifiers.