Abstract: Luus random search algorithm[1] does not converge to the optimal solution when the selected initial value X(0) and initial search region R(0) are not proper. This paper has found out a reason of the fact that the above-mentioned algorithm took a systematic reduction of the size of search region under the constant factor. The modified random search, algorithm has been proposed by the author. The idea of this algorithm lies in that the search region is expanded when the search is proceeding with big strides, vice versa. Thus the search region was reduced from the overall situation, but, on the contrary, it was expanded occasionally from the partial situation. The modified algorithm is noted as below:whether X(0) or R(0) was selected has no influence over the reliability 5 theorically it goes a way towards solving the problem of rather high dimension in theory; it is suitable not only to solving the problem of constrained nonlinear programming but also to that of unconstrained; the feasible region is not necessarily limited on convex region. The application of the modified random search algorithm has been described with illustrations and the comparsion between modified and Luus random search algorithm has made.