The 59-year-old patient, who suffered burns to 98 percent of his body, had been in critical condition since being hospitalized after the fire on Jan. 5, according to Yinchuan's health and family planning commission.
The other 32 people who were injured in the fire in Yinchuan, capital of Ningxia, are in stable condition, the commission said.
The bus burst into flames and was "quickly turned into skeleton" on the morning of Jun. 5. Police suspected it was caused by arson and has detained Ma Yongping on the same day.
Ma is now under arrest in line with an order from the Yinchuan Municipal Procuratorate.
Police said Ma had been in a financial dispute with a construction contractor and expressed his discontent by setting the bus on fire.