The invention relates to a test apparatus for simulating mechanics characteristics of a water-resisting pipe under deepwater drilling well conditions. The test apparatus comprises a supporting device, an ocean wave simulating device, a drilling well simulating device, a water-resisting pipe tensioning system, a water-resisting pipe deflection system, a hydraulic system, an air compression system and a data acquisition system, wherein the drilling well simulating device is connected with the supporting device through the water-resisting pipe tensioning system and the water-resisting pipe deflection system, the supporting device comprises a pool and a bracing frame body erected above the pool, the water-resisting pipe tensioning system comprises a connecting rack, a tensioning ring and a steel wire rope, the ocean wave simulating device comprises four submersible pumps and a water supply system, the drilling well simulating device comprises a drilling rod, a drill bit, an oil cylinder and an oil motor, the hydraulic system is connected with the oil cylinder and the oil motor of the drilling well simulating device, the air compression system is connected on the drilling well simulating device, and the data acquisition system comprises a foil gauge and a foil gauge data acquisition instrument. The apparatus can simulate different conditions encountered by a water-resisting pipe during deepwater well drilling, and is wide in application scope, and high in universality.