Implementing water resource tax policies and enhancing the level of water-saving technology in high water-consuming enterprises are crucial paths to developing water-saving industries and building a water-saving society. However， how government resource regulation policies affect the water-saving technology cooperation and R&D strategies among high water-consuming enterprises remains to be thoroughly explored. In light of this， it constructed non-cooperative R&D decision， two-stage R&D shared incentive cooperation decision， and fully collaborative R&D decision for enterprise water-saving technology under the background of water resource tax， based on differential game theory. Through these strategies， it explored the time evolution trajectory of enterprises’ equilibrium water-saving volume and technology level， and conductd a comparative analysis of enterprises’ equilibrium profits. Furthermore， it utilized the Rubinstein bargaining model to allocate the profits generated by water-saving technology and conducted a simulation analysis and discussion for high water-consuming enterprise A in the pilot area of water resource tax. The results show that under the non-cooperative strategy， there is room for Pareto efficiency improvement in enterprises’ decisions； while the R&D incentive strategy significantly enhance enterprises’ investment in the development of water-saving technology， improve the maturity of water-saving technology， and increase enterprise profits. The degree of effort in water-saving technology R&D is positively correlated with the proportion of profit distribution， and a reasonable profit distribution mechanism is crucial for ensuring continuous enterprise investment in R&D. Additionally， despite being subject to certain conditions， the water resource tax still plays the leverage effect of green taxation， stimulating investment in technology R&D by high water-consuming enterprises. The research findings reveal the driving mechanisms and key factors of water resource tax on the cooperative R&D of water-saving technology in high water-consuming enterprises， offering valuable insights for the sustainable development of high water-consuming enterprises under the background of water resource tax.