The pair have been charged over a controversial land purchase in 2003, and Thaksin must now return to Thailand or face a possible arrest warrant.
They are currently in exile in the UK.
"The judges have agreed to accept the case put forward by prosecutors. The first hearing will be on August 14," Tonglor Chomngarm, head of the panel which will hear the case, said on Tuesday.
A court summons was expected to be delivered to the couple within three days, and prosecutors said that the pair, who are currently in London, must appear at the first hearing to enter a plea.
"The defendants have to come to the court on the first day - after that, they can ask the court to proceed without them," Nanthasak Poonsuk, the prosecutor, said, adding that if they failed to appear, arrest warrants could be issued.
Thaksin and Pojaman are each charged with two violations of anti-corruption laws. Thaksin is accused of illegally influencing a deal to allow Pojaman to buy land from a government agency at a bargain price.
The couple could be jailed for up to 13 years and each face a fine of up to 200,000 baht ($6,250) if convicted.
But Noppadon Pattama, Thaksin's lawyer and spokesman, said that his clients would not return for the opening arguments, as they feared for their safety and did not believe the court could be impartial.
"Both of them will fight the case, but as of now the two defendants will not return to fight the case on the grounds that the judicial process is still being interfered with," Noppadon told the AFP news agency.
"... the two defendants will not return to fight the case on the grounds that the judicial process is still being interfered with"
Noppadon Pattama, Thaksin's lawyer and spokesman
"Both defendants might not get a fair trial ... the team of lawyers will ask the court to postpone the hearing until after the elections."
The military rulers who toppled Thaksin last September have promised to hold general elections before the end of the year.
Should the couple fail to appear, prosecutors could opt not to issue arrest warrants but instead give Thaksin one more chance by sending a summons to Britain and asking for cooperation from the authorities there, Nanthasak said.
Both options would lead to the trial being postponed, he added.
Thaksin was in New York when tanks rumbled onto the streets of Bangkok. He has remained abroad, but stayed in the headlines back home with a takeover bid for British football club Manchester City, which is almost complete.
Pojaman, who is already fighting a court battle over tax evasion charges, has been in and out of Thailand.
She was recently in Singapore for medical treatment, but Noppadon said she joined her husband at their London home a few days ago.
Thailand's Department of Special Investigations has already ordered Thaksin and Pojaman to return home and appear before police by July 27 to face separate charges of making fraudulent filings to stock exchange regulators.
The junta has cited corruption and abuse of power as the key reason for Thaksin's removal from power in last year's bloodless coup, and is under pressure to pin down the billionaire telecoms tycoon on corruption charges.
A number of other cases against Thaksin and his family are slowly making their way through Thailand's legal system.
Anti-graft investigators have already frozen at least $1.52bn of assets belonging to him and his family.