The invention discloses a method for micro-acid pressure composite augmented injection in an offshore high-porosity and high-permeability reservoir. The method comprises the following steps that S1, a target well suitable for micro-acid pressure composite unplugging and augmented injection is screened out; S2; liquid mediums are injected into the target well to break a near-well formation to form micro-cracks and keep the cracks open; S3, an acid liquid system is injected as prepad fluid or subsequent fluid to dissolve and remove inorganic scales in a near-well zone; S4, acidic treatment liquid is injected into the opened cracks for corrosion; and S5, a water absorption index or an daily water injection amount is used for evaluating the effect of the augmented injection; and if organic blockage occurs in the target well, the operation of removing the organic blockage is further included before the step S3, specifically, organic washing liquid is injected into the target well to dissolve and remove the organic scales at shaft bottom and the near-well organic matter damage. The method integrates the technologies such as micro-fracturing cracks, organic solvent cleaning and acid etching crack reforming, realizes the augmented injection of a water injection well in an offshore oil field, and meets the requirement of ''enough injection of water'' in the oil field development and water injection process.