In　this　paper,　we　report　a　novel　motion　style　of　microrobots　actuated　by　magnetic　field.　The　instability　introduced　by　the　alternative　magnetic　field　leads　to　the　stick-slip　pattern　of　microrobot　movement.　And,　by　combining　two　iron　balls　at　microscale　together,　the　dimer　microrobots　are　fabricated　and　studied　in　the　motion　experiment.　The　dependencies　of　stick-slip　motion　speed　on　the　frequency,　waveform　of　actuation　signal　and　the　size　of　both　monomer　and　dimer　microrobots　are　systematically　investigated　to　clarify　the　underlying　mechanism　of　this　motion　style.　Motion　speed　tends　to　increase　as　signal　frequency　increases　first,　and　then　decrease　when　the　frequency　goes　high.　Smaller　size　of　microrobots　can　move　faster.　And　waveform　is　demonstrated　to　have　significant　impact　on　the　motion　speed.　Finally,　we　reveal　that　alternative　magnetic　field　drive　both　monomer　and　dimer　microrobots　with　size　of　hundreds　of　microns　to　move　in　a　stick-slip　style;　and　the　motion　speed　can　be　tuned　through　the　actuation　signal　frequency.　Furthermore,　through　modulating　the　generated　magnetic　field,　the　motion　direction　is　promised　to　be　controlled　as　well.　©　2019　IEEE.