Abstract: Monte Carlo localization scheme with a scan matching algorithm is suggested as a robust localization method for mobile robots to accomplish their tasks autonomously.A normal distributions transform(NDT) which is a new approach to laser scan matching is applied to the scan matching algorithm,and this scan matching method transforms the discrete set of 2D points reconstructed from a single scan into a piecewise continuous and differentiable probability distribution defined on the 2D plane,which can be used to match another scan by using Hessian Matrix.Thereby,no point to point correspondences have to be established.Experimental results show that the robot is able to accomplish localization autonomously in an indoor environment using the natural environmental characteristics.