Based on the pure exchange economic model of Lucas and the partial information assumptions，this paper investigates the effects of over-extrapolation belief biases that the representative agent exhibits in the learning process on the market equilibrium and asset prices. The conclusions show that even with a low coefficient of relative risk aversion，the over-extrapolation belief biases can not only reduce the risk-free rate，but also enhance the risk premium and return volatility of the risky asset. Therefore，this paper provides a unified theoretical framework that can simultaneously explain the equity premium puzzle，interest rate puzzle，and volatility puzzle.