We propose an encoding method which combines Transmit Array Spatial Encoding (TRASE) and spatial encoding magnetic field (SEM) to improve the image quality in a permanent-magnet-array (PMA)-based low-field portable MRI system with acceleration. TRASE is used to introduce phase shift to re-arrange the signal points in local k-spaces, to gain more information quicker to increase imaging quality and speed. A significant quality improvement can be achieved in the reconstructed images, especially in the central regions, which is shown numerically. The number of rotation angles is reduced 80% for the same image quality. The experiments are being conducted for a validation.