A　user-centric　location　privacy-preserving　method　with　differential　perturbations　(Ulp2mDP)　is　proposed　to　solve　the　problem　that　the　location　obfuscation　technique　using　cloaking　region　requires　a　trusted　third　part　(TTP)　and　cannot　sufficiently　prevent　inference　attacks　based　on　background　information,　and　hence　is　easy　to　leak　location　privacy.　The　method　can　enhance　the　user＇s　location　privacy　without　requiring　a　TTP.　The　Ulp2mDP　uses　a　modified　Hilbert　curve　to　project　each　2-D　geographical　location　of　user　into　a　1-D　space,　and　then　randomly　generates　a　reasonable　perturbed　location　by　combining　the　k　anonymity　with　differential　privacy　technique.　The　perturbed　value　is　then　submitted　as　the　user＇s　real　location　to　the　service　provider.　In　order　to　address　the　resource　limitation　of　mobile　devices,　a　quad-tree　based　scheme　is　used　to　transform　and　to　store　the　user＇s　context　information　as　bit　stream,　which　are　highly　efficient　with　respect　to　time　and　space　complexities,　hence　to　achieves　high　precision　of　retrieval.　Security　analysis　shows　that　the　Ulp2mDP　can　effectively　protect　user＇s　location　privacy.　Experimental　evaluation　and　a　comparison　with　the　approach　using　standard　Hilbert　curve　show　that　the　average　retrieval　accuracy　of　the　Ulp2mDP　increases　by　15.4%.　It　is　concluded　that　the　Ulp2mDP　provides　a　tradeoff　between　privacy　preserving　and　service　accuracy,　and　has　a　certain　theoretical　and　practical　significance　for　the　design　of　privacy-preserving　systems.　©　2016,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.