In test and evaluation of complex systems, the number of tests is limited due to constraints in time and cost. Thus, proper designs are needed for test point and sample size. Sequential design is suitable for high-cost tests but its effect is determined by the design criterion and method utilized. To address the problem, design criteria are devised based on Stochastic Kriging. For test point design, a design criterion is established by estimating components of the prediction error and Centered-L2 Discrepancy is introduced to balance exploration and exploitation. For sample size allocation, an integer programming problem with integrated mean squared error as objective function is converted into a multistep decision process and a solving strategy via approximate dynamic programming is proposed with the value function approximated based on the solution of the slack problem. The feasibility and validity of the purposed sequential design method is verified via numerical simulation and real-world flight simulation turntable experiments.