As the core component of the Three Dimensional (3D) printer, the distribution of temperature field has a great influence on the mechanical properties and the forming precision. According to the temperature field distribution of the printing head, Workbench ANSYS is used to simulate the temperature field. Results were shown the cylinder heating rod cannot heat the printing material PLA（Polylactic Acid） uniformly. Therefore, the annular heating rod of the print head was designed, and the temperature field analysis of the print head was done, and the temperature of the heating rod was reduced the temperature of 50 ℃, the PLA of nozzle mouth temperature was increased by 50 ℃. A temperature measurement platform based on thermistor sensor was built. The results between simulation and experiment has the relative error below 20%, and shows that little difference from the simulation results, the designed print head is reasonable, which shows certain application value.