In　this　paper,　effect　of　hold　time　on　the　low　cycle　mechanical　fatigue　failure　behavior　of　Sn3.0Ag0.5Cu　solder　joint　was　investigated.　Fatigue　tests　were　conducted　utilizing　trapezoid　waveform　with　four　hold　times　(0,　2,　5,　10　s)　under　348　K.　The　results　show　that　samples　tested　under　waveform　with　hold　time　has　the　faster　maximum　stress　drop　rate　comparing　to　that　without　hold　time.　Accordingly,　the　fatigue　life　of　solder　joint　is　declined　with　increasing　hold　time.　However,　there　exists　a　threshold　value,　and　when　the　hold　time　exceeds　this　value,　the　fatigue　life　changes　little.　Stress　relaxation　occurs　during　the　hold　time,　which　is　completed　in　a　short　time　under　high　temperature.　Deformation　of　the　solder　joint　is　not　uniform,　which　is　concentrated　in　the　solder　matrix　near　the　substrate.　Micro　crack　initiates　at　the　corner　of　the　solder　joint　and　propagates　in　the　strain　concentrated　zone　with　a　direction　parallel　to　the　applied　load.　In　addition,　Creep　voids　are　observed　from　the　fracture　morphology　of　solder　joints　tested　with　hold　time,　which　nucleate　at　the　slip　bands　and　the　dendrite　boundary　tensile　ledges.　Moreover,　the　fracture　morphology　appears　an　inter-granular　rupture　mode.　However,　for　solder　joints　tested　without　hold　time,　the　rupture　mode　is　trans-granular　with　some　dimples　dispersed　on　the　morphology.