Wo Weihan's final appeal was denied in February and his family was informed Nov. 18 that the Supreme People's Court has approved his execution, Wo's daughter Ran Chen said.
Chen said family members were told to arrange to see him as soon as possible, usually a sign that the sentence is about to be carried out. She said a visit had been arranged for Thursday morning at Beijing's Intermediate People's Court, which is responsible for carrying out the execution.
The court said Wednesday it did not have any information on Wo's case and the Supreme People's Court did not respond to faxed questions on the case.
Chen, an Austrian citizen pursuing graduate studies in Berkeley, Calif., said her 59-year-old father was convicted mainly on the basis of a confession that he later recanted. She said the scant evidence brought by prosecutors never proved the spying charges.
According to a copy of Wo's conviction, his alleged crimes include revealing the health status of an unnamed high ranking Chinese official - information considered state secret by China. Wo was also convicted of passing on data about missile control systems. Chen said that data had been published in a magazine and was only later classified as secret.
Wo was accused of passing the information through a middle man to a group linked to the Taiwanese intelligence agencies.
Taiwan and mainland China divided amid civil war in 1949 and Beijing has maintained a threat to invade the island if it declares formal independence, prompting both sides to spy extensively on each other.
Trained as a medical researcher, Wo ran a medical equipment supply company on the outskirts of Beijing and frequently travelled abroad. He was detained in January 2005, but not permitted to see a lawyer until a year later.
Wo has been held in a prison hospital since March 2005, shortly after suffering a brain hemorrhage. He was sentenced to death by the Beijing court in May 2007 after a closed trial.
His appeal was denied Feb. 29 this year and his sentence automatically forwarded to the supreme court for approval as required by the Chinese legal system.
Although courts have been ordered to apply the death penalty for only the most egregious crimes, China remains the world's leading executioner of prisoners, including many convicted for nonviolent crimes.
Amnesty International recorded 470 executions last year, calling that figure an absolute minimum based on publicly available reports.