A barrier plate for highways comprises a M-shaped protective member made of plastic material and integrally press formed, and including a plurality of trapezoid and spaced projections and concaved planes, each of the projections having integrally formed and spaced first, second and third passages formed in the inner rim thereof and having a warning structure affixed on the outer periphery thereof; a saddle, one side of which is joined with the M-shaped protective member by using a trapezoid elongated retaining portion, made of ABS plastic material and injection molded in the shape of a flat lamination, and including a plurality of corresponding bores provided on one side thereof and a recessed adhesive portion formed on another side thereof; a support, one end of which is inserted in the ground yet another end of which cooperates with the adhesive portion of the saddle, retained by bolts through the M-shaped protective member.