Abstract: Hitachi U-2000 double-beam UV-spectrophotometer the is production of Hitachi in the late 1980 s and early 1990 s.It utilized the Hitachi famous concave diffraction monochromator, the Seya-Namiota optical system and a special computer with 6 809 CPU to insure this instrument stability,credibility, facility and good performance.It is currently available in many fields. This article detailed a frequent troubleshooting of this type instrument.