The girl in the red coat is the most obvious symbol in Schindler’s List, simply because her coat is the only colored object, other than the Shabbat candles, presented in the main body of the film. To Schindler, she represents the innocence of the Jews being slaughtered. He sees her from high atop a hill and is riveted by her, almost to the exclusion of the surrounding violence. The moment Schindler catches sight of her marks the moment when he is forced to confront the horror of Jewish life during the Holocaust and his own hand in that horror.
The little girl also has a greater social significance. Her red coat suggests the “red flag” the Jews waved at the Allied powers during World War II as a cry for help. The little girl walks through the violence of the evacuation as if she can’t see it, ignoring the carnage around her. Her oblivion mirrors the inaction of the Allied powers in helping to save the Jews. Schindler later spots her in a pile of exhumed dead bodies, and her death symbolizes the death of innocence.
This one child is a symbol of all the 6.000.000 victims, exposed to ruthless slaughter.