Two models (Ta and Nanbu) of Coulomb collisions are compared theoretically, and the difference in scatter angle between Ta model and Nanbu model is analyzed particularly. The model of Coulomb collisions between electrons in the code which is developed already with Ta model is rebuilded with Nanbu model. Then, the codes with Ta model and Nanbu model are used for simulating electron energy distribution in JAEA 10 A respectively. The results of simulation are compared with the experimental results, showing that the electron energy distribution is closer to Maxwell distribution with Coulomb collisions and the Nanbu model is more accurate than the Ta model.