The DArk Matter Particle Explorer (DAMPE) is a general purpose satellite-borne high energy γ−ray and cosmic ray detector. Among the scientific objectives of DAMPE are the search for the origin of cosmic rays and an understanding of the Dark Matter particles. As one of the four detectors in DAMPE, the Plastic Scintillator Detector (PSD) plays an important role in the particle charge measurement and the photons/electrons discrimination. It can identify the atomic number Z/charge states of relativistic ions from H to Fe and the detection efficiency for Z = 1 particles can reach 0.9999. The PSD has been working reliably since the successfully launching of DAMPE on December 17, 2015. In this paper, the design, assembly, qualification tests of the PSD and some of the performance measured on the ground are presented in detail.