In this study, selective laser melting (SLM) technology was used to produce test samples and aircraft air inlet protective grilling using TC4 powders. The microstructures and mechanical properties of printed samples were further analyzed. Results indicate that the cross section of fractured longitudinal samples has a fine microstructure, which leads to a strong fine-grain strengthening effect. Thus, superior comprehensive mechanical properties of the longitudinal samples are achieved. Moreover, the microstructure of the printed samples is found to comprise fine acicular α’ martensite. After annealing, the α’ martensites almost completely disappear. A new mixed microstructure comprising packets of the Widmannstatten and basket-weave microstructures is formed. The as-annealed samples possess high ductility and toughness with relatively inferior strength. In addition, the mechanical properties of as-annealed samples are equivalent to those of the as-forged ones. Based on the above-mentioned experimental results, the aircraft air inlet protective grilling of TC4 was prepared via SLM. The dimension precision of the unit grids is better than ±0.1 mm. Moreover, the manufacturing periodicity is reduced from seven to four days.