In　this　paper,　a　series　of　Montmorillonite　I　Crosslinked　polyethylene　(MMT/XLPE)　nano-composites　were　prepared　though　melting　blend　method,　before　which　the　MMT　had　been　modified　by　Octadecyl　ammonium.　Two　types　of　organic　modifiers　(E　EA　and　EVA)　were　used　to　control　the　dispersion　state　of　MMT　in　XLPE.　X-ray　diffraction　(XRD)　and　scanning　electron　microcopy　(SEM)　were　used　to　represent　different　influences　of　two　organic　modifiers　on　the　dispersion　of　MMT　Nano-additions　in　XLPE.　The　result　shows　the　interlayer　spacing　of　MMT　has　increased　from　2.5nm　to　3.6nm　and　3.7nm　by　adding　EEA　and　EVA,　respectively,　which　devotes　to　the　melt　intercalation　of　MMT　in　XLPE.　Accelerating　water　tree　aging　tests　were　performed　on　the　nanocomposites　and　water　trees　were　observed　by　a　microscope.　According　to　the　result,　it　can　be　concluded　that　with　the　same　addition　of　MMT,　composites　using　EEA　as　organic　modifier　have　an　obvious　decrease　in　water　tree　length　(58.9%　along　the　electrical　field　direction　and　19.9%　in　vertical)　compared　with　the　XLPE　sample.　Besides,　water　tree　length　of　composites　using　EVA　as　organic　modifier　has　a　decrease　of　65.0%　along　the　electrical　field　direction　and　37.1%　in　vertical,　which　means　EVA　has　a　more　remarkable　contribution　to　the　water　tree　retardant　property　of　MMT/XLPE　nanocomposites.