解:∵x,y>0,且x+y=4,∴1x+4y=(1x+4y)(x+y4)=14(5+yx+4xy)≥14(5+2×2)=94,当且仅当y=2x=83时等号成立.故m≤94,即实数m的最大值为94.故答案为:94