This article studies discrete-time high-order fully actuated (HOFA) adaptive stabilization control for a type of combined spacecraft simulator (CSS) with unknown parameters. First, discrete-time second-order fully actuated systems are modeled for the CSS system and generalized to a general discrete-time HOFA system with unknown parameters, followed by a control objective. Then, a discrete-time HOFA adaptive stabilizing controller including the state feedback and the parameter estimate is designed using discrete-time Lyapunov theories to realize a Schur-stable closed-loop system with an arbitrarily assignable eigenstructure. Using the arbitrariness of the eigenstructure configuration, the control performance can be further improved by multi-objective optimization design. Finally, the proposed technique is successfully employed to solve the stabilization task of the CSS with unknown parameters, verifying its convenience and effectiveness in practice.