Although it is a loop line, trains returning to the depot use Yishan Road as a terminal to let all passengers disembark.

[4] At 4 o'clock in the morning on July 1, 2003, the Pudongnan Road-Nanpu Bridge section of Line 4 suddenly saw water seepage during the construction of the connecting passage between the upper and lower tunnels.

At 9 o'clock in the morning, the podium of a nearby building on South Zhongshan Road collapsed; beginning in the early morning of the July 2, the flood wall of Dongjiadu Waima Road section began to sink and crack due to the settlement.

[7][8] Line 4 has been operating over capacity due to large passenger flows for a number of years.

In June 2021 it was announced that Shanghai Metro has started to update of the signal system and finish before December 31, 2024.

CASCO successfully won the bid for the renewal and transformation of the signaling using Qiji TACS system.