This article constructs a collaborative innovation decision-making model for the new energy vehicle industry chain under decentralized and carbon quota sharing contracts, and obtains the optimal parameter values and profit values of the new energy vehicle industry entities under two different scenarios. Taking BYD's new energy vehicle industry as a case study, the beneficial effect of carbon sharing contracts on the collaborative decision-making of the new energy vehicle industry system is empirically analyzed. Research has found that although carbon sharing contracts may weaken the willingness of new energy vehicle battery suppliers to innovate in carbon reduction, they will effectively improve their innovation in the range of new energy vehicles. The market price of new energy vehicle manufacturers under carbon sharing contracts decreases with the increase of the carbon sharing coefficient. Carbon sharing contracts can significantly increase the profits of the main players in the new energy vehicle industry system, and are directly proportional to the carbon sharing coefficient of the contract.