Water-in-crude oil emulsions stabilized by natural surface-active components (such as asphaltene) are one of the major problems in relation to petroleum production. New water soluble nonionic amphiphilic block and graft copolymers based on hydrophilic PEG and PPO were prepared. PEG-PPO-PEG copolymers were prepared in the normal condition by two methods to use them as demulsifiers for crude oil emulsions. The first step in this work is to polymerize propylene glycol and propylene oxide to produce poly (propylene glycol) PPO. The reaction time was adjusted to produce PPO having different molecular weights. The molecular weights of the prepared PEG-PPO-PEG block and graft copolymers were determined by GPC technique. The surface activity of the prepared surfactants was determined from the surface and thermodynamic properties of these surfactants. The evaluation of the prepared copolymers as demulsifiers for water-in-crude oil emulsions was carried out.