In order to reveal the mechanical characteristics of foamed ceramics and further verify the plastic deformation characteristics, the foamed ceramics were tested with constrained axial crushing. In view of the problems to hold the compression head properly and keep the axial alignment with a compression head, a cylindrical constraint, a specimen and the experiment machine, a set of simple and practical experimental devices was designed and optimized, including a simple fixture to hold the compression head and a freely skidding platform to keep real-time alignment of the head and constraint. The yield limit and elastic modulus of foamed ceramics with different densities were obtained based on experimental results, and the Poisson ratio was calculated to be 0.100 9 and 0.073 45 with empirical formulas based on obtained yield limit of two different density groups-heavier and lighter, respectively. The two-sample t-test of the yield limit and elastic modulus reveals that there is no statistical difference between the unconstrained and constrained experimental yield limits and elastic modulus, and the Poisson ratio of the foamed ceramic is not statistically nonzero.