Abstract: Firstly, the thermal error testing of the turning machine tool feed axis, including thermal error testing and temperature rise testing of the heating part, as well as the instruments used and the methods followed for testing, were introduced. Secondly, the common support structures for the X-axis of Turning machine tool, such as “back to back” structure, “face to face” structure, and “face to face with padding” structure, were elaborated. Thermal error tests were conducted on the X-axis of different support structures to obtain thermal error test data. Finally, a cause analysis was conducted on the test results, revealing the variation patterns of X-axis thermal errors with different support structures. The conclusion was drawn that the “back to back” support structure is the optimal structure, and suggestions for reducing feed axis thermal errors were given for machine tool use.