Ms Yingluck could be removed from office and banned from politics for five years if found guilty.
The decision is expected on Wednesday, the court said after the hearing.
The prime minister`s supporters believe the top courts are biased against her and the case is an attempt by the elite to force her from office.
The BBC`s Jonathan Head in Bangkok says if the Constitutional Court also bans enough of her cabinet to disable her caretaker administration, her ministers have warned there will be chaos, with large-scale protests by pro-government red-shirts a certainty.
Thailand has seen deadlock since anti-government protests began in 2013. The protesters, who are mainly urban and middle class, want Ms Yingluck`s government replaced by an unelected "people`s council".
In response, Ms Yingluck called a snap election in February which she was expected to win, but this was disrupted by the protesters and subsequently annulled.
`No benefit`
The prime minister is also facing several other legal challenges.
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