A method of preparation of trientine tetrahydrochloride crystals in which an anti-solvent at a feeding temperature is added into a trientine tetrahydrochloride solution and stirred for crystallization wherein the feeding temperature ranges from 50 C. to 75 C. and the anti-solvent is an alcohol solvent. A novel trientine tetrahydrochloride featuring XRPD peaks detected at 21.9, 24.8, 25.2, 28.0 and 35.60.1 2 for stable storage of a pharmaceutical composition manufactured with the trientine tetrahydrochloride.