Avani was the defending champion in the women's 10m Air Rifle Standing SH1 event.
She had won the yellow medal in Tokyo.
Avani, who was left paralysed below the waist following a car accident when she was just 11, scripted a remarkable journey in her sporting career and became the first Indian female shooter to win a medal in shooting in the Paralympics in 2021.
Setting a new record, she scored a final tally of 249.7 to win the gold medal in the ongoing mega event, giving India a strong start to the medal chase.
She surpassed her Tokyo record of 249.6 points.
Competing her first Paralympics, Mona Agarwal scored 623.1 to settle for bronze.