The result matched her fourth-placed finish in the T35 200m final last Friday.
Warner, 38, was the eldest in the final – 10 years older than Ping Liu, who won the gold medal with a new world record time of 15.44sec.
Italy’s Oxana Corso finished second in 15.94sec, with Canada’s Virginia McLachlan third in 16.42sec.
Warner, who received a massive cheer by the 80,000-strong crowd when her face appeared on the big screen before the race, was then fourth home in 16.90sec.
All eight runners beat the previous Paralympic record of 20.33, set by Aoife O’Brien in Barcelona in 1992.