2D　inter-symbol-interference　(2D-ISI)　channel　models　ultra-high-density　magnetic　recording　systems,　which　suffer　from　ISI　in　the　down　track　direction　and　inter-tack　interference　along　the　cross-track　direction.　These　interferences　seriously　degrade　the　performance　of　the　magnetic　recording　systems.　Low-density　parity　check　(LDPC)　codes　was　used　in　storage　systems　However,　although　non-binary　LDPC　codes　with　log-BP　decoding　was　designed　for　2D-ISI　channels,　it　has　a　drawback　of　a　high　decoding　complexity.　To　address　this　issue,　this　paper　proposes　a　simplified　iterative　decoding　for　2D-ISI　channels.　In　specific,　we　use　extended　min-sum　(EMS)　decoding　with　truncation　of　messages　to　simplify　computation　and　optimize　scale　factor　in　outer　iteration　by　the　EXIT　analysis　to　improve　the　performance.　Finally,　the　simulated　results　show　that　the　proposed　scheme　with　reduced　complexity　for　2D-ISI　system　can　maintain　an　approximate　performance　to　traditional　one.　Even　at　high　SNR　regions,　the　proposed　scheme　will　be　better　than　previously　decoding　algorithm.　©　2020　IEEE.