If you have a Green card and is arrested for Domestic violence but was not convicted and the DA's office dropped the case. - Will affect the Citizenship process

Yes. Depending on the actual charge and the state statute. Please note that you don't have to have a conviction to get have immigration problems regarding naturalization and maintaining permanent residence. Being charged could be a problem, pleading to the essential elements could be a problem. The USCIS is very strict regarding domestic violence, CSA and firearms violations.

Get your charging documents and the court disposition/dismissal and consult with an experienced immigration attorney before filing for naturalization. If this was helpful rate this answer, good luck!