In comparison with those prepared by ordinary hot extrusion method, the 17-4PH stainless steel fabricated by laser directed energy deposition (DED) has finer grains and retained austenite. However, current research mainly focuses on its mechanical properties, and there is still a lack of studies on its passivation and pitting corrosion behavior. In this work, the microstructural characteristics, passivation, and pitting behavior in 3.5%NaCl solution of 17-4PH stainless steel prepared with three different DED heat inputs were assessed by taking the hot extruded 17-4PH steel as comparison, via potentiodynamic polarization curves, electrochemical impedance spectroscopy, potentiostatic polarization, critical pitting temperature, and Mott-Schottky curves, as well as XRD, SEM, EBSD, and XPS. The results show that the DED steel prepared with a heat input of 1440 J·cm^-1 contains 6.9% retained austenite (EBSD volume fraction). Compared with the hot extruded steel the lath martensite size of DED steel is reduced by 67.5%, the pitting potential is increased by 0.131 V (vs. Ag/AgCl), the resistance to metastable pitting is higher, the critical pitting temperature is elevated from 47.9 ^oC to 67.2 ^oC, besides, the point defect density is lower and the Cr oxide content is higher for the passivation film. These findings indicate that the DED sample has stronger passivation ability and superior pitting corrosion resistance.