This paper presents the results of perturbation structure study for some near-Earth asteroids (NEA) (3200 Phaethon, 137924 2000 BD19, 374158 2004 UL и 2008 FF5) with perihelion distances less than 0.14 AU. We have considered following disturbing factors: perturbations from major planets, the Moon, Pluto, Ceres, Pallas, Vesta; perturbations from solar pressure; perturbations from relativistic effects from the Sun; perturbations from Earth and Sun oblateness. The results have been obtained by five different methods. 1) The moment of the best conditionality has been determined on the interval of observation from MPC. The improvement of the orbital elements has been made when using of the full model. The orbital evolution has been investigated with varying models without one any perturbation. The difference between position vectors of full model and without any factor has been used as investigated parameter. 2) As in the previous method the moment of the best conditionality has been determined on the interval of observation from MPC but improvement of the orbital elements and orbital evolution have been implemented with the same model without one perturbation. The investigated parameter is the same as in previous method. 3) The maximum values of the instantaneous acceleration have been calculated. 4) The standard error (O-C) with full model and with varying models has been calculated. 5) Position and size of the initial probability domain has been evaluated based on covariance matrix, parameters of the initial orbit and accuracy of initial data. The results obtained by different methods are in good agreement with each other’s and allow do the following reasonable conclusions about influence of perturbing forces on the asteroids motion. Perturbations from planets and the Moon certainly should be taken into account because these perturbations are strong or medium. Perturbations from relativistic effects and Sun oblateness also should be considered because these perturbations are comparable with ones from the Moon. Solar radiation pressure could be important factor for an asteroid dynamics. For Phaethon this perturbation is rather weak, but depends on physical parameters known not well enough. That is why this perturbation may be ignored. The perturbations from Ceres, Pallas, Vesta, Pluto and the Earth oblateness are weak for these objects and also may be ignored. The asteroid 2008 FF5 deserves a special attention. This object has been observed on short time interval. That is why orbit improvement is not able for some force models. For this asteroid only first and third methods are informative. The application of these methods shows necessary of account of relativistic effects and Sun oblateness. Thus we recommend the following force model for investigation of dynamical properties of objects with small perihelion distances: perturbations from planets, the Moon, relativistic effects from the Sun and the Sun oblateness.