This is a combined list of the Spur (联络线), Parallel (并行线), Metropolitan Area Ring (都市圈环线) and City Ring (城市环线) routes of National Trunk Highway System Expressways of China.

Before 2017, those codes were followed by a cardinal point (N, S, E, W) and an additional digit if repeated starting with 2; associated auxiliary expressways were followed by two additional digits, but during the 13th National People's Congress in 2017, the SAC published a new recommendation national standard GB/T 917-2017, in this standard document, all auxiliary routes are ruled only having two additional digits, and therefore all parallel routes and most of city ring routes are having their codes changed.

[1] China contains large groups of areas that are sparsely populated; expressways in these areas are therefore usually not designated principals, except when connecting provincial capitals with Beijing (G6, G7) or part of the Eurasian Land Bridge (G30, also the more practical route for Xinjiang to connect with Central and Southern China).

However, in plans for 2035 all prefecture-level capitals and an absolute majority of counties must connect to the NTHS network, even in those remote areas, resulting in extremely long branch expressways (spur routes) of the NTHS, including but not limited to G0611, G0612, G0613, G0615, G1013, G1816, G5511.

The routes are officially printed in the 2022 National Highway Network Plan.