A new source location method is proposed based on the relation between the trilinear coordinates of the source and the area of basic triangle.Heron-Qinjiushao formula is used to calculate the area of triangles.The location region of the source is determined and the trilinear coordinates of the source are corrected by using the constraint on area of triangles.Simulation studies show that the presented method outperforms the traditional method by reducing the standard deviation for scenarios with large non-line-of-sight errors.