The short answer is tricky. Officially, Call of Duty: Black Ops was never released on the PlayStation Portable (PSP). However, a modified version exists: Call of Duty: Black Ops: Declassified (officially for PS Vita) and fan-made ISO mods of Call of Duty: Roads to Victory .
The PSP hardware (333 MHz CPU, 64 MB RAM) could not realistically run the Black Ops engine, which was built for Xbox 360/PS3/PC. Call Of Duty Black Ops Ppsspp Game Download