Abstract: Existing squarified treemap layout algorithms are inefficient in sequentiality, and ordered treemap layout algorithms are incapable of squarified ability.In this paper we propose an squarified and ordered treemap layout algorithm, called SOTLA.First, artificial nodes with large values are created by binding nodes.Then, nodes are layouted by letting the average aspect ratio being 1.0 along the shortest edge.Each bundle node is handled in a fashion of divide-and-conquer.The above process is repeated for each node.We test our approach with a dataset of 50 groups of pesticide residues, whose values have large disparity.We compare our approach with conventional Squarified, Pivot, Strip and Spiral layout algorithms in views of average aspect ratio, continuity, readability, and average of distance change and variance of distance changes.Experimental results show that our SOTLA algorithm has significant advantages on continuity and average aspect ratio, and fair performance in terms of readability, average of distance change and variance of distance changes.