Line 6 is part of the Phase III expansion of the Shenzhen Metro with a construction time frame scheduled for 2015–2019.

Guangming station (formerly known as Cuihu) will have provision for interchange with Dongguan Rail Transit Line 1 which is also under construction.

By 2003, Line 6 was again redesigned into a 51.8 km (32.2 mi), 15 station, commuter railway in a "∩" shape connecting the Airport with Longhua District via Songgang.

[12] In order to promote better transport integration and economic development between Dongguan and Shenzhen with the relevant departments of the two cities working together in rail transit planning.

[15] This revised Phase III plan showed that Line 6 will extend further south into central Shenzhen with six new stations, and an additional length of 11.5 kilometers.

The Shenzhen Metro Phase III approved by the National Development and Reform Commission does not include the south extension of Line 6.

[16][17] Funding was approved in April 2013 and construction of the first phase from Shenzhen North Station to Songgang officially started on August 25, 2015, with completion by June 2020.

[3] However, due to later negotiation failures between the two parties, Shenzhen Metro Corporation took over the project themselves without the BOT contract as planned.