In this study, Polyamide 12 (PA12) powder recycled after selective laser sintering (SLS) was made into filaments for fused deposition modelling (FDM). Compared with fresh PA12, the melt flow rate (MFR) of the recycled PA12 powder decreased by 77%, but the mechanical properties were only slightly reduced. In FDM, the printing speed and building orientation were changed, and the performance of the printed parts was tested. If the printing speed is too fast or too slow, the mechanical properties of the parts will be affected, and there is an optimal speed range. The tensile strength, flexural modulus, and impact strength of a printed test sample made from recycled powder reached 95%, 85%, and 87% of an x-direction test sample made from fresh PA12, respectively. For test samples printed from different orientations, the mechanical properties of the test samples printed in the x-direction were the best, while the crystallization performance was the opposite. Scanning electron microscope (SEM) images show that the printed test sample had good compactness and mechanical properties, and the delamination phenomenon was basically not observed.