Equity financing activated the ability of the upstream and downstream of collaboration supply chains of growth-type enterprises to capture opportunities for development． However，the arbitrage pricing theory could not alleviate the conflict of valuation between the investment and financing sides，which makes it more urgent to explore a reasonable valuation of equity financing.This paper depicts the essential characteristics of supply chains and game theory in a new perspective，constructs a retailer equity financing model and analyzes the cooperative and win-win situation to mitigate the valuation conflict．In addition，the paper also discusses the existence of a reasonable valuation in equity financing．The key finding is that there exists a“cooperative valuation interval”and an optimal valuation.At the same time，the optimal valuation is affected by the retailer in supply chain structure．