This paper studies the problem of H-2 norm checking for a MIMO system with parameter uncertainties. Under the assumptions that the coefficients of the numerator polynomial of the system's transfer function are multi-affine functions of the uncertain parameter that varies in a convex polytope, and that the coefficients of the denominator polynomial of the system's transfer function are affine functions of the uncertain parameter which varies in a convex polytope, a vertex checking result is obtained.