Does Swahili has prepositions

Yes, but not many. Unlike English and other western languages, prepositional meanings are usually expressed in the forms of verbs or nouns. A few examples:

VERB: Kupika, to cook; kipikia, to cook for. Nilipika maini i(I cooked liver), niliwapikia watoto maini (I cooked liver for the children).

NOUN: Nyumba, house or home. Nyumbani, at home, to home, around home, from home, etc. Hii nyumba yetu, this is our house. I'm going home, Ninakwenda nyumbani.

A FEW PREPOSITIONS: katika (in, inside), juu ya (on or over), chini ya (under), kwa (to, for, by). There are few of them, and their translations depend on context.