Theformula of finding the volue of a sphere was discovered independently in China and Greece. Il was well-know that Archimedes of Syracuse discovered and proved the formule of finding the volume of a sphera with right circular cones and circular cynlinders. Credited to Liu Hui’s commentaries on Jiu Zhang Suan Shu, or nine chapters on the Art of Mathematics, ZU Geng also fond out the same formula by comaring spheres to a special solid called Mouhefanggai, which is also know as Bicylinder Steinmetz solid. While understanding the formula of finfing the volume of a sphere is included in Hong Kong-s Mathematics Curriculum in Key Stage 3 (junior secondary education), it is worthwhile to compare the mathematical methods used in the discoveries and study the possible impact to students’ development in the ability to « thik mathematically ».