Abstract: The effects of the difference between the tensileand compressive properties (TCPs) of materials on the final topologies ofstructures are investigated with floating reference intervals in theoptimization case of a bone growing process based on Wolff's law. There aretwo aspects in the difference on TCPs of basal materials to have equivalenteffects on the structural topology optimization: one is the differencebetween their tensile and compressive Young's moduli, , the other is thevariation of the intervals of their references strains in bone growingprocess under the tensile or compressive state . The numerical cases verifythis equivalence and further reveal a more reasonable structure topologysubjected to the differences on TCPs of the materials.