Ms Tida said the rally would be called when the Constitutional Court announces "judgement day".
The rally would be peaceful and weapons-free, she said.
The former UDD chair said she believed the Constitutional Court, the National Anti-Corruption Commission and the Election Commission had already made their decisions in the cases against Ms Yingluck.
She accused the agencies of holding double-standards - a cause of political chaos.
If the prime minister was found guilty, the UDD would rise to struggle, which would be heightened to achieve victory, she added.
Ms Tida also asked why the EC and the Constitutional Court had not taken legal action against People's Democratic Reform Committee (PDRC) secretary-general Suthep Thaugsuban for having admitted in his speech that he had successfully engineered the nullification of the Feb 2 election.
Mr Suthep also declared he would obstruct an election in every way, indicating that he and the PDRC had impeded democracy, she said.
She called for the EC to hold a clean and fair election and not use delaying tactics in the hope of bringing about chaos.
An election was the only way out for the country, Ms Tida added.