Abd al-Karim al-Khaiwani, editor-in-chief of Shura opposition newspaper, was found guilty by a court in September of supporting rebel cleric Husain al-Huthi.
The appeals court also imposed a six-month ban on his publication and ordered seven other journalists working for the same newspaper to be questioned on similar charges.
Al-Huthi, a leader of the so-called Believing Youth group, was killed by security forces in September for setting up unlicensed religious centres and forming an armed group which had staged violent anti-US protests.
Anti-US sentiment is high in Yemen and other countries in
the Middle East over the presence of US troops in Iraq, and the Israeli-Palestinian conflict.