The　operation　of　an　all-optical　magnetic　switching　based　on　the　paramagnetic　NaTb　(WO4)2　crystals　is　carried　out　by　the　time-resolved　magneto-optical　Faraday　effect.　Our　results　demonstrate　that　the　switching　time　can　be　as　fast　as　∼500　fs　at　room　temperature.　The　switching　amplitude　shows　a　linear　dependence　on　the　excitation　intensity,　which　is　proportional　to　the　magnetization　induced　by　the　circularly　polarized　light.　Based　on　the　inverse　Faraday　effect　in　magneto-optical　crystal,　the　switching　mechanisms　arising　from　circular　dichroism　and　birefringence　are　discussed.　By　tailoring　the　magneto-optical　properties　of　NaTb　(WO4)2　crystal,　the　switching　magnitude　can　be　modulated.　©　2010　American　Institute　of　Physics.