Farshid Yadollahi, a lawyer for the group, says a court in the southern city of Qom found the 52 guilty of disobeying the police and disturbing the peace.
The cases follow an incident in February, in which some 1,000 Sufis were arrested during clashes with the police sparked by an order to shut down a Sufi seminary in Qom. Most were later released.
The court also sentenced Yadollahi himself. He says he has been banned from practicing law for five years.