The black box will be given to officials for encryption, Chinese TV reported on Saturday while an Iranian team is in China to follow up issues related to accident.
The dead bodies of three Iranian crew members have so far been found.
The Iranian tanker carrying condensates collided with a Chinese freight ship in East China coast last Saturday, and its 32 crew members, 30 Iranian and two Bangladeshis, went missing.
According to Iran's Consul General in Shanghai Alireza Irvash, the operation to put out the fire of the Iranian tanker began on Wednesday while flames of fire subsided despite bad weather in the region.