Taking tetrahydrofuran copolyether （PET）-based high energy solid propellant as the research focus， the 3D printed propellant was designed and formulated with PET/nitrate（NG/BTTN） as the binder system modified by shaping agent（MS）， ammonium perchlorate（AP） as the solid filler and polyfunctional aliphatic isocyanate （N-100） as the curing agent. The shaping effect of MS at 25 ℃， its compatibility with each component， and its rheological properties at 25， 35， 45， 55 ℃ were studied. The reasonable range of the processing parameters for 3D printing such as temperature， nozzle diameter and pressure were determined preliminarily by simulation. The results show that MS has good compatibility with PET/NG/BTTN and AP in the propellant， and it also improves the safety performance of the propellant to a certain extent. The obtained slurry exhibits the temperature-sensitive characteristics， capable of achieving good setting effect at 25 ℃. By applying the determined printing parameters involving the temperature of 50 ℃， the nozzle diameter of 1.2 mm and the pressure of 11 kPa， the actual printing rate can be approached to 8 mm·s^-1， which is the first time that the 3D printing of PET based high-energy solid propellant to be realized.