1.2cm ovarian cyst with t1&t2 hyperintense signals which persisted bright in t2fs seq on mri.can it be endmeriosis or anything besides hemorhegic cyst?

Endometriosis: could also manifest as cysts with hemorrhagic internal contents. However, usually there are other findings, not just a solitary cyst. Sometimes a cyst with internal proteinaceous content could cause the signal characteristics you describe. However, the vast majority of the time, the cyst you describe is simply a functional hemorrhagic cyst.