Sun, 67, has in the past spoken out about human rights and politically sensitive topics.
He was found guilty of “picking quarrels and provoking trouble” – a charge often used against activists.
Sun’s company is among China’s biggest, with businesses ranging from meat processing and pet food to schools and hospitals.
Sun is said to be close to some prominent Chinese political dissidents and has in the past criticised the government’s rural policies.
Sun reportedly denied many of the accusations against him in a pre-trial hearing, describing himself as an “outstanding Communist party member”.