Biodegradable polyurethane with N-(2,4,6-trichlorophenyl)maleimide (TCPM) pendant groups has been prepared via a combination of a thiol-ene click reaction and a condensation reaction. The TCPM moieties acting as antifoulants are released as the polyurethane degrades in the marine environment. The biodegradation and hydrolyzation of the polyurethane were investigated by use of quartz crystal microbalance with dissipation (QCM-D) and hydrolysis experiments. It shows both the enzymatic degradation rate and the hydrolyzation rate decrease with TCPM content, which facilitates increasing the duration of the polyurethane. Marine field tests reveal that the polyurethane has good antifouling ability since the degradation leads to a self-renewal surface and the release of the antifoulants is controlled.