Yingluck is charged with negligence for allegedly failing to prevent corruption and irregularities in the scheme.
The Supreme Court’s Criminal Division on Political Office Holders is set to deliver a verdict in the case on August 25.
The supporters began arriving at the court at about 5am.
Also there were Pheu Thai Party leaders Sudarat Keyuraphan, Watana Muangsook, Surapong Tovichakchaikul, Nuttawut Saikuar, Tida Tavornseth and Weng Tojirakarn.
Yingluck was set to arrive at the court at about 8.30am.
Her lawyer said her closing statement has 20 pages and cover six aspects.