Prosecutors alleged Guo was secretly employed by a Chinese spy agency and passed on information about negotiations and decisions in the European Parliament, collected personal information on AfD leadership and spied on Chinese opposition figures and dissidents.
They also accused him of being the handler for a second spy, a Chinese national identified by authorities as Yaqi X., who did not work for Krah.
Prosecutors requested seven-and-a-half years in jail.
Krah, who is no longer an MEP and serves as a lawmaker in the German Bundestag, has long maintained his ignorance about the allegations against Guo and testified in court earlier this month that he hired Guo for his language skills and experience.
But Krah himself has been investigated for taking bribes from both China and Russia and was questioned by the FBI over the matter. His offices were raided by German police this month and the German parliament has revoked his immunity.