In this paper we have studied the trend and bias of technological change in Iran’s cement industry by dual cost function approach. This approach is useful to estimation of factors demand structure with regard to changes of factors price and technological situation. We estimated a translog cost function in addition to equations system of cost share, using Seemingly Unrelated Regression Equation (SURE) approach during the period 1355-1385. The results show that the rate of technological change has been -1.12 percent during the studied years. It means that there is a decrease in rate of cost of productive units along with time. Furthermore, the results indicate that technological change has been biased towards the use of more energy.