The three-day convention is being organised at the newly-built Janeshwar Mishra Park in Lucknow.
Mulayam's tenure as SP chief will last for three years.
More than 10,000, delegates attended the convention which marks 22 years of the party's formation. Party representatives from Kerala, Tamil Nadu, Bihar, Lakshadweep, Manipur, Goa, Odisha, Gujarat, Karnataka, Himachal Pradesh, Rajasthan, Assam, Chhattisgarh, Uttarakhand, Telangana, West Bengal and Madhya Pradesh have taken in the meet.
During the three-day meet, the party will look for new political alternatives and alignments to counter the emerging challenges on the political horizon.