Abstract: In this paper, we study the downlink transmission mode in the three-dimension multiple-input multiple-output (3D MIMO) system for users with statistical channel state information (CSI) and instantaneous CSI. The design problem of downlink precoding for mixed utilization statistics and instantaneous CSI is solved. Based on the properties of the Kronecker product of 3D MIMO channel, an extended zero-forcing precoding method for minimizing the total transmit power of the base station is proposed, and the optimal horizontal precoding matrix and optimal vertical precoding matrix are solved respectively. Simulation results show that the scheme has lower complexity and good rate.