NOVELTY - A crystal A of piperaquine phosphate comprises X ray powder diffraction diagram expressed by number of 2 theta diffraction angle, and X ray powder diffraction diagram provided with characteristic peaks at 5.8, 9, 9.6, 11.8, 12, 13.3, 13.5, 16.5, 17.2, 18.1, 19.8, 19.9, 20.1, 22.6, 24.2, 24.3, 25.1, 27.3, 27.6, 28.4, 29.9 and 33.3 plus minus 0.2 degrees .    USE - Crystal A of piperaquine phosphate.    ADVANTAGE - The method has low toxicity, is environment-friendly, has simple operation, and is suitable for industrial production.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a preparation of piperaquine phosphate crystal A comprising adding 4,7-dichloroquinoline into liquated piperazine hexahydrate, heating, condensing, and obtaining 7-chloro-4-(1-piperazine)quinoline; condensing onto 7-chloro-4-(1-piperazine) quinoline and trimethylene chlorobromide, and obtaining piperaquine; dissolving piperaquine into water, heating at 90-95 degrees C, adding phosphoric acid, filtering reaction mixed product, and cooling filtrate to 35-45 degrees C; and cooling to 30-50 degrees C, standing at 20-30 degrees C to crystallize, and obtaining piperaquine phosphate crystal A;    (2) a crystal B of piperaquine phosphate comprising X ray powder diffraction diagram expressed by number of 2 theta diffraction angle, and X ray powder diffraction diagram provided with characteristic peaks at 3.8, 7.8, 11.8, 13.4, 16.2, 18.1, 18.2, 19.9, 22.6, 22.7, 24.3 and 25.8 plus minus 0.2 degrees ;    (3) a preparation of piperaquine phosphate crystal B comprising suspending piperaquine phosphate crystal A into ethanol, stirring for 3-5 days at room temperature to 50 degrees C, filtering and obtaining piperaquine phosphate crystal B;    (4) a crystal C of piperaquine phosphate comprising X ray powder diffraction diagram expressed by number of 2 theta diffraction angle, and X ray powder diffraction diagram provided with characteristic peaks at 3.7, 5.8, 9, 9.5, 11.3, 13.3, 17.2, 18.1, 19.8, 22.6, 22.8, 24.3, 25.2, 27.2 and 29.8 plus minus 0.2 degrees ;    (5) a preparation of piperaquine phosphate crystal C comprising suspending piperaquine phosphate crystal A into acetone or acetonitrile, stirring for 3-5 days at room temperature, filtering and obtaining piperaquine phosphate crystal C;    (6) a crystal D of piperaquine phosphate comprising X ray powder diffraction diagram expressed by number of 2 theta diffraction angle, and X ray powder diffraction diagram provided with characteristic peaks at 3.8, 7.8, 11.8, 12.6, 13.4, 15.3, 16.2, 18.1, 18.2, 20.1, 22.6, 24.2, 24.3 and 25.1 plus minus 0.2 degrees ;    (7) a preparation of piperaquine phosphate crystal D comprising suspending piperaquine phosphate crystal A into acetone or methanol, stirring for 3-5 days at room temperature to 50 plus minus 2 degrees C, filtering and obtaining piperaquine phosphate crystal D;    (8) a crystal F of piperaquine phosphate comprising X ray powder diffraction diagram expressed by number of 2 theta diffraction angle, and X ray powder diffraction diagram provided with characteristic peaks at 3.8, 7.8, 11.8, 13.4, 16.2, 18.1, 18.2, 19.9, 22.6, 22.8, 24.3 and 25.2 plus minus 0.2 degrees ;    (9) a preparation of piperaquine phosphate crystal F comprising suspending piperaquine phosphate crystal A into acetonitrile, stirring for 3-5 days at 50 plus minus 2 degrees C, filtering and obtaining piperaquine phosphate crystal F;    (10) a crystal G of piperaquine phosphate comprising X ray powder diffraction diagram expressed by number of 2 theta diffraction angle, and X ray powder diffraction diagram provided with characteristic peaks at 9, 9.6, 11.8, 12.0, 13.3, 13.5, 16.5, 17.2, 18.1, 19.8, 19.9, 20.1, 22.6, 24.2, 24.3, 25.1, 27.3, 27.6,28.4, 29.9 and 33.3 plus minus 0.2 degrees ; and    (11) a preparation of piperaquine phosphate crystal G comprising suspending piperaquine phosphate crystal A into water, stirring for 3-5 days at room temperature, filtering and obtaining piperaquine phosphate crystal G.