As the International Maritime Organization (IMO) tightens its requirements on greenhouse gas emissions from shipping, the imperative for carbon emission reduction in maritime transport is pressing. In the short to medium term, the Onboard Carbon Capture and Storage (OCCS) system combined with low-carbon fuel can be seen as an effective way to reduce CO2 emissions in ships. Presently, the technology of the OCCS system remains in its nascent stage, which necessitates further refinement. Based on the existing OCCS techniques, the efficient utilization of waste heat and cold energy from ships and further coupling with green renewable energy, hold the key to achieving highly integrated marine carbon capture systems, which not only meet the IMO long-term goal requirements for EEDI but also present the optimal choice for significantly reducing the economic costs associated with the OCCS system.