The 74-year-old woman, surnamed Jiang, fell down in Dazhou City in Sichuan Province but later blamed three children who helped her for causing the accident and demanded compensation.
Family of one of the three children complained to the police that they were forced to pay USD 166 towards medical expenses of the old woman.
But after investigating the case, police said Jiang had fallen on her own and her action amounted to extortion.
Instead, her son, surnamed Gong, received 10 days in detention and a fine of 500 yuan, state-run Xinhua news agency quoted local police as saying.
China has reported a spate of cases in recent years about "good samaritans" being framed by elderly people they helped.
Experts say the country needs to enhance legal protection for good samaritans in order to prevent such incidents from discouraging public acts of kindness.