This is the dramatic moment a brave onlooker rescued a woman whose car had crashed into a river.

Sun Xichun, 60, a Tai Chi master who had been training nearby, leapt into the water to save the stranded driver at the Jiuqu River in Danyang, China.

Local media reported that the motorist mistakenly pressed the accelerator instead of the brake while trying to park, causing the vehicle to smash through a guardrail and plunge into the water.

Footage shows the woman clinging to the floating white electric car while Sun holds onto her as they are swept along by the current on September 21.

Heroic Sun can be seen paddling with one arm while keeping the victim above water with the other.

Moments later, crew members on a passing ship threw a life jacket into the river after bystanders raised the alarm.

After fastening the orange inflatable vest onto the woman, Sun guided her towards the bank, where several men were waiting to pull her to safety.

Two locals crossed over the barrier to grab her while others supported them to prevent the men from slipping into the river.

The crowd then helped Sun out of the water after securing the driver.

Witnesses said emergency services were called immediately, with some onlookers searching for lifebuoys and ropes.

Paramedics arrived and took the driver to the hospital. She reportedly did not sustain any life-threatening injuries.

Authorities later used a crane to recover the submerged vehicle.