The invention relates to a sand box with a convenient box locking tool. The sand box comprises an upper box body, a middle box body and a lower box body which are sequentially stacked. Hanging lugs are arranged on the left side and the right side of each box body respectively. A locking device is symmetrically arranged on the front side and the rear side of the box bodies. The sand box is characterized in that the locking device comprises a lower support arranged on the lower box body, two upper supports arranged on the upper box body, a vertical rib and a cross arm, the two upper supports are arranged at the equal height, the two ends of the cross arm are borne on the two upper supports, the bottom of the vertical rib is hinged to the lower support through a limiting pin, the top end of the vertical rib penetrates out of a central hole of the cross arm, a vertical wedge groove is formed in the top end of the vertical rib, a wedge block is installed in the wedge groove, and the wedge block is squeezed between the wedge groove and the top face of the cross arm.