Last month, Lula's hand-chosen successor, Brazil's first female president, Dilma Rousseff was found guilty by the Senate for breaking budget rules and dismissed from the presidency.
Her succesor, former vice president Michel Temer, has abruptly pulled the country to the political and economic right, trying to boost Brazil out of its worst economic recession since the 1930s.
Moro's decision may prevent Lula from making a political comeback in the 2018 presidential campaign.
Despite the corruption allegations facing the PT and several of its former coalition parties, the most recent polls have shown Lula remains a leading candidate for 2018.
Lula was charged with three counts each of corruption, which carries a maximum sentence of 16 years per count, and money laundering, with a possible sentence of up to 10 years per count.
If found guilty, however, the sentence would be determined by the judge.