Properties of a free-standing diamond wafer with a diameter of 80 mm and a thickness of 900~950 $mu extrm{m}$ deposited by the multi-cathode direct current plasma assisted chemical vapor deposition (MCDC PACVD) method were investigated. Defects of the diamond film were observed by optical transmission microscopy and its crystallinity was characterized by Raman and IR spectroscopy. Defects were distributed partially on boundaries of the grain. In the grain, (111) plane contained a higher defect density than that on (100) plane. FWHM of Raman diamond peak and IR transmission at 10.6 $mu extrm{m}$ were 4.6 $ extrm{cm}^{-1}$ /~5.3 $ extrm{cm}^{-1}$ and 51.7 ~ 61.9 %, and their uniformity was $pm$7% and $pm$9%, respectively. The diamond quality decreased with going from center to edge of the wafer.