The invention discloses a peroxide molybdate crystal containing rare-earth Eu3+ ions; the molecular formula of the peroxide molybdate crystal is (NH4)14 {[Eu(H2O)4 ] 4 (MoO4)[Mo7 O22 (O2)2]4}.8H2O; the synthesis method comprises the steps: weighing (NH4)6 Mo7O24.4H2O with weight of 1.236g and mole ratio of 1 mmol and dissolving in distilled water with volume of 20ml to prepare ammonium molybdate solution; stirring at room temperature, dripping 3% H2O2 with weight of 0.453g and mole ratio of 4 mmol at the speed of 30 drops every minute to the ammonium molybdate solution, and stirring for 30 min; dripping 5ml of aqueous solution containing Eu(NO3)3.6H2O with weight of 0.446g and mole ratio of 1 mmol, continuously reacting for 30-60 min at room temperature; filtering, standing the filtrate for 4-5 days at room temperature, and separating out yellow block-shaped crystals; the peroxide molybdate crystal contains rare-earth Eu3+ ions and peroxide groups in the structure, has good catalytic and oxidative activities for the substances such as alcohol and aldehyde and has potential application values in fluorescent radiation materials and catalytic materials.