Abstract: In the environment of carbon emissions cap and trade policy, the uncertainty of carbon emissions price has an important impact on the low carbon technology investment timing choice of the supply chain enterprises. By using the real option theory, the research investigates the option value of low-carbon technology investment in supply chain under uncertainty of carbon price and establishes a basic decisions model of low-carbon technology investment timing in supply chain. Based on the above basis, the paper constructs a low-carbon investment game model taking into consideration cooperation and competition relationship within the supply chain, and then emphatically discusses the equilibrium strategy decisions involving investment timing and proportion of transfer payments made by upstream and downstream enterprises in the supply chain. Based on the above models, the influence factors of low carbon technology investment opportunity are analyzed by numerical examples. The research results show that the factors such as the reduction rate of carbon emissions, the fluctuation rate of carbon price and the transfer payment proportion between firms have impacts on the threshold of low-carbon investment. In order to achieve the twin objectives of higher economic efficiency and more carbon emission reduction, and attain the supply chain coordination and the win-win situation between enterprises, the enterprises of supply chain should comprehensively evaluate the option value of low-carbon technology investments and reasonably select the best equilibrium of investment timing and transfer payments proportion.