Considering that there exists conformity effect in the real social network, the dynamic descriptions of the probabilities of rumor spreading and a spreader coming to reason were improved. A rumor spreading model with conformity effect was proposed, and the corresponding equations of transmission dynamics were established based on the different network topologies. In the rumor spreading model with conformity effect, numerical analysis of eventual scale of rumor spreading was conducted, and the results show that the eventual scale of rumor spreading increases with the initial probability of rumor spreading. Matlab simulations of the model show that conformity effect will accelerate the rumor spreading. Monte Carlo method was utilized to simulate the rumor spreading in the small-world network and the scale-free network, and results show that under the influence of conformity effect, the rumors are spreading faster and deeper in the scale-free network. The simulations of the improved model based on the real social network show that the influence of the initial rumor spreader exerts a great impact on the process of rumor spreading.