Through expounding the service condition of extrusion cylinder for aluminum extrusion press, several factors affecting the extrusion cylinder failure were analyzed. The results show that the material creep curve of the liner should be closed to that of the jacket, the sharp corners should be avoided during structure design, and the strength and temperature measurement accuracy should be also considered; the isothermal extrusion in constant speed extrusion is realized by cooling the extrusion cylinder; the temperature control of extrusion cylinder is essential; during the extrusion cylinder heating before extruding, the back and forth ends of the inner hole must be blocked so as to keeping the liner warm.