We report the results of a weakly-interacting massive particle (WIMP) dark matter search using the full 80.1;live-day exposure of the first stage of the PandaX experiment (PandaX-I) located in the China Jin-Ping Underground Laboratory. The PandaX-I detector has been optimized for detecting low-mass WIMPs, achieving a photon detection efficiency of 9.6%. With a fiducial liquid xenon target mass of 54.0,kg, no significant excess event were found above the expected background. A profile likelihood analysis confirms our earlier finding that the PandaX-I data disfavor all positive low-mass WIMP signals reported in the literature under standard assumptions. A stringent bound on the low mass WIMP is set at WIMP mass below 10,GeV/c$^2$, demonstrating that liquid xenon detectors can be competitive for low-mass WIMP searches.