The atomic structure of the perfect AlPdMn icosahedral phase has been studied on a single crystal specimen by quantitative convergent beam electron diffraction (QCBED) technique in combination with describing the shape of atomic surface by symmetry-adapted series of surface harmonics. The spherical model was used as the starting model for the refinement. By fitting the calcu lated electron diffraction intensities to the experimental line scan profile, the coefficients in the surface harmonics expansion of the boundaries of atomic surface are refined. The refined parameters show that the fluctuations of the external boundary of atomic surface for Pd at n0 can be as large as 0.2 nm. The boundaries of a tomic surfaces for Mn show little fluctuation. In the present model,the number of unphysically short interatomic distances is significantly reduced in comparison with the spherical model.