Aligned electrospun fibers are of great importance to many practical applications (e.g., tissue engineering, electronic devices, and fiber-based reinforcement) because of the anisotropic arrangement, but their preparation remains complicated. Herein, a facile yet effective method for preparing uniaxially and radially aligned electrospun fibers is developed by delicately employing an insulating and hydrophobic collector in the electrospinning setup. Based on this technique, aligned fibers with high quality can be readily obtained. Importantly, it is shown that the hydrophobicity of the substrate and low relative humidity of the electrospinning environment play a key role in the alignment of obtained fibers, which can effectively increase the charge density of the fiber and promote the degree of alignment. A possible mechanism for the formation of aligned electrospun fibers on insulating collector is proposed, which lies in the interplay of two main factors of electric field force and Coulombic interactions between the charged fibers and plane of the collectors. Also, by using a laser scattering methodology, qualitative and quantitative evaluation of the orientation of fibers is carried out. Moreover, electrospun fibers with radially aligned arrangements can be obtained by tuning the shape of the substrates. This study provides a versatile strategy for producing aligned electrospun fibers on a wide range of substrate materials, expanding their applications in photonic and electronic devices.