In recent years, electric heaters have been widely used in electric storage systems and nuclear power plant regulator temperature control. As a key component of electric heaters, electric heating tubes have received limited research attention. In this study, Ansys Fluent finite element simulation software was used to establish a coupled model. By varying the outer diameter and axial pitch of the resistance wire, we investigated the impact of resistance wire structural changes on temperature distribution and flow field characteristics in electric heating tubes. The results show that both the maximum internal temperature of the electric heating tube and the average temperature of the metal shell first increase and then decrease with increasing spiral outer diameter. Among the five outer diameters tested, the 9.2 mm outer diameter configuration achieves the most uniform temperature distribution. Furthermore, as axial pitch increases, both the maximum internal temperature and average shell temperature also exhibit an initial rise followed by a decline. Of the five axial pitches studied, the 5 mm pitch yields the most uniform temperature distribution.