The purpose of this study was to establish a numerical computation model for estimation of oxygen uptake (VO₂) kinetics in decremental load exercise (DLE) starting from a work rate (WR) above the ventilatory threshold (>VT). In the model, WR in DLE were separated into several steps (constant load exercise, CLE) of which the durations increased step by step. VO₂ kinetics in each step was estimated using an exponential equation, and the sum of VO₂ values from all steps at a given time was regarded as simulated VO₂ in DLE. In the model, the time constants were set symmetrically in a step <VT and asymmetrically in a step >VT at onset and offset (τ_off) of exercise. As a result, simulated VO₂ qualitatively, but not quantitatively, approximated measured VO₂. Consequently, we incorporated a new model in which a step >VT was subdivided into several parts. Although there was a slight difference quantitatively, the interval of subdivision of 3.0 min and τ_off of 2.8 min allowed for qualitative approximation. The numerical computation model adopted in this study is useful for estimation of VO₂ kinetics during DLE starting from high intensity (>VT).