The invention discloses an FCC equilibrium catalyst reactivation and modification method. The method comprises following steps: (1) ammonium ion exchange: mixing an FCC equilibrium catalyst with water, carrying out pulping to prepare FCC equilibrium catalyst slurry, heating the slurry to a temperature of 50 to 95 DEG C, mixing the slurry with ammonium salts, carrying out ammonium ion exchange for1 to 3 hours under stirring, and performing filtering, washing, and drying, wherein after ammonium ion exchange, the Na2O content of the FCC equilibrium catalyst is reduced to 0.2 wt% or less; and (2)mixing the FCC equilibrium catalyst, which has a Na2O content of 0.2 wt% or less and is obtained in the step (1), with water, carrying out pulping, mixing obtained slurry with magnesium salts and phosphor containing compounds, stirring, carrying out co-precipitation for 10 to 60 minutes, and finally performing filtering, drying, and burning to obtain reactivated FCC equilibrium catalyst. The provided method can recover the catalytic cracking activity of an FCC equilibrium catalyst and improves the selectivity of cracking products. The method is simple, is easy to perform and is environmentally friendly at the same time.