This paper describes exciting force models about jumping up and down, which has the biggest exciting force among human motions. First part describes a large floating floor which can be regarded as a SDOF and its transfer characteristics. Second part describes experiments of jumping up and down with from one to sixteen people on the floating floor and how to analyze the experiment results. Final part proposes dynamic load coefficients α1 ～ α6 in consideration of relations between the number of excitations and exciting forces of jumping up and down.
