An antenna multiplexing system and a method of a smart antenna and a Multiple-Input Multiple-Output antenna are provided, wherein the system includes a MIMO antenna array and a smart antenna array, the smart antenna array includes several groups of antenna array elements in which the distance between neighbor antenna array elements is less than or equal to one half of wavelength, and the smart antenna array comprises at least two groups of antenna array elements with the coherence sufficient for the requirement of the MIMO applications. The method includes: in accordance with the type of the data to be transmitted, determining a transmitting mode and processing the data to be transmitted accordingly, and in accordance with the transmitting mode, controlling the MIMO antenna array or smart antenna array, so as to transmitting the data to the mobile terminal. With the premise that the actual coverage of TD-SCDMA system should be further improved, the requirement of higher user throughout could be met, and the MIMO antenna system could satisfy the requirement of the future system evolution. Both of the applications of the MIMO and the smart antenna could be met with the use of the same antenna feeding system, and the adaptive switching of the MIMO and the smart antenna with respect to the user could be achieved.