The interfacially active asphaltenes (IAA, 1.75 wt % of the total asphaltenes) from Indonesian asphalt rocks have been proven to be the major component in stabilizing the water-in-oil (W/O) emulsion (stable even over 1 year) than other fractions in asphalt (i.e., asphaltenes, maltenes [asphalt without asphaltenes], and remaining asphaltenes [asphaltenes without IAA]). The droplet size of the IAA-stabilized emulsion was determined to be in the range of 10 to 20 mu m. To demulsify this extremely stable emulsion, we synthesized a novel polyether demulsifier (JMNP) with rich oxygen by simple esterification and polymerization. When applying the JMNP and commercial demulsifiers (polyethylene glycol (PEG8000), SP169, PE1951, and AP2050) in breaking this emulsions, results showed that all of them could demulsify the IAA-stabilized emulsions. It is also found that the JMNP performs well in enhancing the demulsification of the IAA-stabilized emulsion, achieving complete dehydration of the emulsions in 30 min at 60 degrees C and 400 ppm. The types and number of oxygen-containing groups (hydroxyl, ester group, polyethylene oxide segment, and polypropylene oxide segment) in the demulsifiers are considered to play the key role in breaking of the IAA film and finally the coalescence of the water droplets. This primary test suggests that JMNP would be a potential candidate for the demulsification of water-in-heavy oil emulsions.