The charges relate to his brief imposition of martial law in December 2024, which prosecutors allege was a plot to consolidate power.
Investigators claim Mr Yoon and his former defence minister planned to provoke an armed aggression from North Korea to justify the martial law declaration.
Mr Yoon, who was impeached and arrested, has consistently rejected the accusations, insisting the declaration was within his presidential authority.
The Seoul Central District Court is expected to deliver its ruling on the case in February.