The Jiaolong, depending on local weather and sea conditions, will dive six times, deeper and deeper, to try a new dive record.
The first dive will challenge the depth of over 5,000 meters, but less than 6,200 meters. The fifth and sixth dives are scheduled to challenge the depth of 7,000 meters.
The six dives will test various functions and performances of the manned submersible at great depths.
Each dive may last for eight to 12 hours.
The Jiaolong succeeded in diving 5,188 meters in the Pacific Ocean last July, enabling China to conduct scientific surveys in 70 percent of the world's seabed areas.
"Before the formal sea dives, a comprehensive review of the submersible as well as its support system will be taken," on-scene commander Liu Feng told Xinhua on the Xiangyanghong 09, the mother oceanographic ship of the submersible.
Experts say, for safety, sea dives can only be conducted in daylight under no-more-than-four-class wind and no-more-than-three wave.