The invention discloses a safety belt for tying a baby on a bed. The safety belt mainly comprises two fixing belts, a binding belt, a sleeving ring and four positioning rings. The two fixing belts intersect with each other, the binding belt is fixed to an intersection of the fixing belts, a connecting fastener is arranged at the tail end of the binding belt, one end of the sleeving ring is fixed onto an annular fastener, and the other end of the sleeving ring penetrates the annular fastener and then is connected onto the connecting fastener of the binding belt. The safety belt has the advantages that a user can firmly grasp the annular fastener with one hand and pulls the sleeving ring between the annular fastener and the connecting fastener towards the direction of the connecting fastenerwith the other hand, and accordingly the size of an inner hole of the sleeving ring can be diminished; the fixing belts which intersect with each other can be fixed onto a mattress by the aid of thepositioning rings, the sleeving ring sleeves the waist of the baby, then the tail end of the sleeving ring can be connected with the binding belt fixed into the intersection of the fixing belts, and accordingly the baby only can act around the center of the bed in the ranges defined by the binding belt and the sleeving ring and can be prevented from falling off from the bed.