The invention discloses a three-dimensional shock insulation device and method based on horizontal motion shock insulation. The three-dimensional shock insulation device includes a top X-direction shock isolator, a middle Y-direction and Z-direction shock isolator and a lower support, and the top X-direction shock isolator includes a top connection plate, a top end plate, an X-direction guide rail, an X-direction spring, an X-direction damper and an X-direction sliding block; the middle Y-direction and Z-direction shock isolator can convert vertical motion into horizontal motion through mechanical motion between internal parts and achieve shock insulation in two directions at the same time, and the middle Y-direction and Z-direction shock isolator includes a triangular steel plate, a plateside guide rail, a Y-direction sliding block, a Y-direction guide rail, a Y-direction spring, a Y-direction damper, a middle end plate and a middle connecting plate; and the upper part of the lower support is fixedly connected with the middle connecting plate, and the lower part of the lower support is fixedly connected with a lower structure. The three-dimensional shock insulation device can beapplied to civil buildings, bridges, underground buildings and other structures being subjected to the earthquake action or other dynamic action, the springs and a limiting device inside the three-dimensional shock insulation device can realize shock insulation and absorption in three directions and the self-resetting effect under different circumstances.