The YF-20 is a Chinese liquid-fuel rocket engine burning N2O4 and UDMH in a gas generator cycle.

The high altitude variation is known as the YF-22 is normally paired with the YF-23 vernier to form the YF-24 propulsion module for second stages.

New versions when used individually for booster applications are called YF-25.

It is usually bundled into modules of multiple engines.

[10][14][15] The relevant modules for first stage application are: The relevant modules for second stage application are: