High-G training for pilots has commonly performed in the centrifuge-based flight simulators. In this paper, algorithms for overload simulation in a threeaxis human centrifuge are developed and validated. To this end, a kinematic model is established for kinematic analysis. A moving average algorithm is employed to smooth the inputs and to alleviate the abrupt changes in pitch and roll angles of the centrifuge. An optimization algorithm for overload simulation is proposed and verified. The algorithm minimizes the error between the simulated and expected overloads to find the optimized kinematic variables of each axis of the centrifuge. Numerical results show that: (1) the moving average algorithm substantially alleviate the abrupt changes in pitch and roll angles of the centrifuge. (2) the proposed optimization algorithm is more accurate compared to traditional algorithms.