Natural capital, ecological products and ecological product values constitute an interdependent relationship of stock, flow and value.Natural capital protocol is a new system of tools borrowed from the financial system that can quantitatively assess the value of ecological products transformed from the stock of natural capital through a market cell like an enterprise.This paper introduces a new protocol conducted by the Natural Capital Coalition, named Natural Capital Protocol, which assesses value through the core concepts of "impact" and "dependence" of enterprise activities, and provides a framework for valuation that includes four logical stages and nine steps.The four logical phases include:a structuring phase to determine the reason for conducting natural capital protocol; a scoping phase to define what should be included in the assessment, a metrics and valuation phase to guide how to measure and assess natural capital; and an application phase to help interpret the results and determine the next steps.Valuation methods include a variety of qualitative, quantitative and monetary approaches.This market-based approach to assessing the value of ecological products, with the enterprise as the smallest unit, finds an anchor of value for the protocol, which can change the situation of passive environmental management and help create positive incentives to create new dynamics of economic growth.Once the value of ecological products is realized, a government-led, market-driven, intermediary organization can be established to actively participate in the promotion system.And with the help of property rights trading and investment and financing mechanism innovation, we can promote the construction of ecological civilization.For China's natural resource management departments, natural capital protocol can also promote natural asset management, and guide and assess market and management subjects.