Can I get married if I’m from Haiti and I have a tourist visa for the US?

A Haitian visitor may marry a U.S. Permanent Resident, but that will not automatically create any authorization for the Haitian spouse to remain in or work in the U.S. Analysis of immigration options for the Haitian spouse will depend upon many details not included in your question. It would be wise for you and your fiance to consult with an immigration attorney who, after learning all of the relevant information about you, your immigration-related history, your fianc? and your goals, will be able to advise about immigration eligibilities, options and strategies.