Open-cell porous elastomer has been widely used in many fields, including filtration film, mechanical dampener, mircofluids devices, and medical implants. While a number of intelligent techniques have been developed to fabricate rigid porous polymers, only limited work has been reported on porous elastomers processing. In this work, the authors specially designed a microsphere-templating casting process for fabricating interconnected porous elastomer and investigated its mechanical behavior. The process started with preparation of a porous wax template via thermal sintering. Then, low viscosity monomers for elastomeric polysiloxane were cast into the wax template. Finally, after curing of the elastomer, the wax component was removed by either mechanical forces or solvent extraction. The resulting material was found to contain a unique co-continuous structure having micropores interconnected by microchannels. The deformation characteristics and mechanical properties of the porous elastomer under tension and compression were then studied. For both tensile and compressive tests, the mechanical properties measured were found to largely deviate from those calculated by the additive rule assuming affine deformation. This non-affine mechanics was further verified by microscopic observations. Cyclic loading and unloading tests were also performed to study the hysteresis of the material. In comparison with the solid elastomer, the hysteresis of the porous elastomer was considerably higher and more sensitive to the strain rate. An attempt was further made to fit the stress-strain curve using existing hyperelastic models, and the results showed that the Arruda-Boyce model, in general, fit both the solid and porous polysiloxane very well.