To optimize the composition of grout materials for offshore wind suction bucket foundations and verify the recyclability of suction buckets after construction with different grouts, 18 fluidity tests, 21 unconfined compressive strength tests and 6 suction bucket recovery tests were carried out to investigate the influence mechanisms of water-solid ratio (0.75, 1, 1.1, 2.5) and bentonite content (0%, 20%, 40%, 60%, 80%, 100%) on the fluidity and compressive strength of grout materials, as well as the recyclability of suction buckets in clay with different grouts. The results show that at a fixed water-solid ratio, the fluidity and compressive strength of grout materials decrease significantly with the increase of bentonite content, and the grout basically loses fluidity when the bentonite content is no less than 60%. At a fixed bentonite content, fluidity increases with rising water-solid ratio (210-290 mm for 20% bentonite content), while compressive strength decreases accordingly. Suction buckets with grouts containing 60% and 100% bentonite can be successfully recovered by positive-pressure water injection inside the bucket. In contrast, grouts with 0% and 20% bentonite content fully solidify and completely block the water injection port, leading to recovery failure. It is recommended that the initial fluidity of grout be controlled within 250-300 mm and the fluidity after 30 min be no less than 200 mm. A bentonite content of 60% is preferred, and the water-solid ratio shall be increased until the required fluidity range is satisfied to balance the requirements of constructability, structural strength and recyclability.