Bangkok police said that about 4,000 police were deployed in the court area, and checkpoints were also set up.
Yingluck has been accused of neglecting responsibility in the rice subsidy program for farmers, purchasing rice at a market price 50% higher. This policy benefits farmers, but causes the government to lose about 8 billion USD due to rice inventories.
Former Prime Minister Yingluck denied the delay, saying she was only responsible for the policy, not managing the plan day by day. Yingluck's government was overthrown in the 2014 military coup.
In the northeastern province of Khon Kaen, where the rosy movement to support the Shinawatra ethnic group flourished, people felt disappointed. "Some want to publicly prove that they are disappointed in the way Yingluck is treated," Reuters quoted the leader of the Reds as saying.
The Pheu Thai Party supports the Shinawatra family, which has declared its disapproval of acts of violence and called on people to gather peacefully.
Some supporters outside the palace in Bangkok carried roses, while others wore white gloves with the words "love".
Before sentencing Yingluck, the court will issue a verdict on former Commerce Minister Boonsong Teriyapirom, who was accused of forging rice sales agreements between Thailand and China in 2013.
If convicted, Yingluck could face up to 10 years in prison, and will have 30 days to appeal.
