She is charged with two counts of misappropriation of public funds, three counts of embezzlement and four counts of forgery.
Castro worked at Halldale Elementary, where she was given responsibility for two school accounts shortly after being assigned to the campus in 2005, according to the District Attorney's office.
She also was made treasurer of the PTA and given access to its checking account, prosecutors said.
Castro is accused of stealing from the three accounts between June 2005 and September 2009, and forging signatures on more than 100 checks by using the names of two different principals and two different PTA officials.
She is due back at the downtown Los Angeles courthouse on Oct. 27 for a hearing to determine if there is sufficient evidence for her to stand trial.