My father married two women, Basically my half sister and I share same father (biological) but we have different mothers. Can I marry my half sister's daughter(my half niece) ?
You can not, your half-sister is your mahram, and so is her daughter.
حُرِّمَتْ عَلَيْكُمْ ... وَبَنَاتُ الْأُخْتِ
Prohibited to you [for marriage] are ... your sister's daughters ...
From Tafsir Qurtubi:
والأخت ٱسم لكل أُنثى جاورتك في أصليْك أو في أحدهما
"Sister" is the name of every female who is your sibling, from both sides or just one.