The accident happened yesterday when the child, who was left unattended while his mother went to a nearby restroom, played at the escalator before falling over and trapped, the People's Daily reported.
He was rushed to hospital but died later.
Hongqiaohegou subway station staff shut off the escalator after 20 seconds.
It was the fourth such accident in over 2 months, sparking concerns over the safety of over 2.4 million escalators currently being used in China.
In August, a cleaner at a mall in Shanghai had his leg amputated as it got stuck in an escalator.
