The invention relates to the field of equipment shock absorption, aims to solve the problem that existing equipment design mounting cannot meet the safety demand of reducing earthquake damage of equipment, and provides an equipment mounting structure, a compound shock isolating support and a rigidity adjusting method thereof. The rigidity adjustable compound shock isolating support comprises at least one shock isolating support and at least one slippage support. The shock isolating support is configured to be vertically supported and connected between a base and to-be-supported equipment. Theslippage support is configured to be vertically supported between the base and the to-be-supported equipment and to form a slippage pair in the horizontal direction between the base and the to-be-supported equipment. The shock isolating support and/or the slippage support is provided with a vertical rigidity adjusting hole for assembling a rigidity adjusting rod which provides extra vertical rigidity when the total vertical rigidity is insufficient. The equipment mounting structure provided by the invention has the beneficial effects that the vertical rigidity and the horizontal rigidity thereof can be adjusted conveniently to meet the demand of to-be-mounted equipment on the vertical rigidity and the horizontal rigidity, the shock resistance is improved, and the earthquake damage is reduced.