Pascoe swam a time of 1 minute 2.65 seconds - almost two seconds faster than her heat time, where she had also broken the record.
The gold is Pascoe's third at Rio and comes came a day after smashing the record in the women's 200m individual medley SM10 event.
She has now equalled New Zealand record for the most Paralympic medals won by an individual athlete along with Eve Rimmer's 14 medals.
In other racing, Mary Fisher finished sixth in the women's 50m freestyle S11 final.
