Before revision:  We present the uncertain risk premium which is distributed with Max distributionN( \underline{\mu , ,\{0\ closed form of bid and ask prices of the European contingent claim against  risky asset with G-asset price system , and give the bid and ask prices are the viscosity solution to nonlinear HJB .
After revision:  We present the uncertain risk premium which is distributed with Max distributionN( \underline{\mu , ,\{0\ closed form of bid and ask prices of the European contingent claim against risky asset with G-asset price system as the discounted conditional G-expecation of the claim, and the bid and ask prices are the viscosity solution to nonlinear HJB .