What can I do if my employer is harassing me and I am on his h1b?

Your best advice will be in a consultation where the background can be better covered. At a minimum, a telephone conversation may work. Is the reason for the harassment clear? Have you kept a record? At minimum, keep a ledger showing dates, times and details (including names of people that were present). If there is anything concrete, such as e-mails or voice messages, certainly retain those.