The Follow-up X-ray Telescope (FXT) is one of the key payloads onboard EP. It is a Wolter-I type X-ray focusing telescope equipped with two telescope modules (focal length 1.6 m), with a total effective area of ~ 600 cm2 at 1.25 keV and an energy range of 0.3–10 keV. FXT is mainly composed of an X-ray focusing mirror assembly (MA) and a camera assembly with a PNCCD detector module. The two FXT modules are completely independent from each other, thus avoiding a single point failure. We completed the internal composites of FXT structural design, which meets the function and performance requirements of mechanical, thermal, contamination control and X-ray optics. The FXT passed successfully the mechanical, thermal qualification level tests on the spacecraft platform in the phase C. [ABSTRACT FROM AUTHOR]