The　H13　steel　block　was　successfully　prepared　by　cold　metal　transfer(CMT)　wire-arc　additive　manufacturing　(WAAM)　method.　The　microstructure　characteristics　and　mechanical　properties　of　the　printed　block　were　both　studied　by　experiments.　It　was　found　that　there　were　obvious　difference　in　the　microstructure　and　mechanical　properties　between　the　central　part　and　overlapping　parts　of　the　printed　block.　It　was　shown　from　the　microstructure　observation　that　the　printed　block　was　mainly　composed　of　martensite　and　residual　austenite.　There　was　an　obvious　primary　austenite　grain　boundary　observed　in　the　base　phase.　In　addition,　compared　with　the　overlapping　part,　the　content　of　residual　austenite　in　the　central　part　was　lower.　It　was　shown　that　the　average　value　of　the　microhardness　in　the　central　part　was　596HV,　while　it　was　534HV　for　the　overlapping　part　due　to　the　higher　content　of　residual　austenite.　Tensile　tests　were　conducted　for　different　direction　of　the　printed　block.　Micropores　with　a　volume　of　100-400　mu　m3　were　observed　in　the　printed　block,　with　90　%　of　the　micropores　in　the　range　of　100-200　mu　m3　in　volume.　The　micropores　were　uniformly　distributed　in　the　sample.　The　presence　of　micropores　leads　to　the　low　elongation　and　tensile　strength.