The invention provides a low-polarity resin and a preparation method and application thereof. The low-polarity resin is of a structure shown by a formula I, and is prepared through three steps of reactions, namely, allyl etherification, rearrangement and end blocking on phenolic hydroxyl through a hydroxyl end-blocking
reagent containing a unsaturated double-bond group on the basis of phenolic compounds or resin. The molecular formula of the resin does not contain a polar
hydroxide radical, the molecular structure is stable, the polarity is low, and reaction activity is high; in the application and
processing processes, no polar
hydroxide radical is generated, thus the influence of a secondary
hydroxide radical on the property of a product of the resin is avoided, and the
dielectric property is improved; the resin comprises the high-activity unsaturated group, the high-
temperature resistance property is significantly improved through a crosslinked curing reaction with other resin, andthus the
dielectric constant and the
dielectric loss of the resin are significantly decreased; and the resin is applied into preparation of laminated boards coated with
metal foil, the dielectric constant and the
dielectric loss of the laminated boards coated with the
metal foil are decreased advantageously, the high high-
temperature resistance property is achieved, and thus the laminated boards coated with the
metal foil have the good comprehensive property.