Freehand three-dimensional (3D) ultrasound imaging usually uses a moving elevation focused one-dimensional (1D) transducer to construct a series of B-mode slice images, and then these B-mode slice images are combined to form a 3D volume image. This method has poor elevation resolution and low frame rate. In this paper, a novel 3D imaging method with a moving 1D array transducer is proposed. Different from the freehand 3D reconstruction, a linear array transducer without elevation focusing is used in the proposed method, and the 1D transducer transmits limited diffraction beams and receives echo signals repeatedly when moving along the elevation direction. After finishing the scanning, all the received signals are combined to construct the 3D image in Frequency domain with Fourier transform. Simulation results show that compared with the freehand imaging method, the new method can improve the elevation resolution significantly, and the resolution keeps almost fixed in the axial direction. The elevation resolution can be promoted to less than 2 mm with the imaging depth 100 mm by one transmission at each position. Besides, because only one transmission is needed at each position, the frame rate can be increased to some extent.