An antenna system, comprising an antenna array, a control unit, a reconfigurable network unit, and K radio frequency channels, wherein the antenna array comprises L antenna subarrays, wherein L is a positive integer greater than 1; the reconfigurable network unit is configured to: divide the L antenna subarrays into M antenna subarray groups, and separately connect the M antenna subarray groups to the K radio frequency channels, wherein one polarization direction of one antenna subarray group is connected to one radio frequency channel; and M is a positive integer, and K is an integer multiple of M; any one of the K radio frequency channels is configured to perform signal processing on a signal received by a connected antenna subarray group and/or a to-be-transmitted signal; and the control unit is configured to control the reconfigurable network unit to adjust a mapping relationship between an antenna subarray group connected to at least one of the K radio frequency channels and the antenna subarrays to switch between a horizontal coverage mode, a vertical coverage mode, and a horizontal and vertical coverage mode of the antenna array, wherein the control unit being configured to control the reconfigurable network unit to adjust a mapping relationship between an antenna subarray group connected to at least one of the K radio frequency channels and the antenna subarrays comprises: the control unit is configured to control the reconfigurable network unit to adjust a quantity of antenna subarrays in the horizontal direction comprised in the antenna subarray group connected to the at least one of the K radio frequency channels, wherein beams generated by antenna subarray groups that comprise different quantities of antenna subarrays in the horizontal direction have different widths in the horizontal direction; and the control unit is configured to control the reconfigurable network unit to adjust a quantity of antenna subarrays in the vertical direction comprised in the antenna subarray group connected to the at least one of the K radio frequency channels, wherein beams generated by antenna subarray groups that comprise different quantities of antenna subarrays in the vertical direction have different widths in the vertical direction. the antenna array comprises L antenna subarrays, wherein L is a positive integer greater than 1; the reconfigurable network unit is configured to: divide the L antenna subarrays into M antenna subarray groups, and separately connect the M antenna subarray groups to the K radio frequency channels, wherein one polarization direction of one antenna subarray group is connected to one radio frequency channel; and M is a positive integer, and K is an integer multiple of M; any one of the K radio frequency channels is configured to perform signal processing on a signal received by a connected antenna subarray group and/or a to-be-transmitted signal; and the control unit is configured to control the reconfigurable network unit to adjust a mapping relationship between an antenna subarray group connected to at least one of the K radio frequency channels and the antenna subarrays to switch between a horizontal coverage mode, a vertical coverage mode, and a horizontal and vertical coverage mode of the antenna array, wherein the control unit being configured to control the reconfigurable network unit to adjust a mapping relationship between an antenna subarray group connected to at least one of the K radio frequency channels and the antenna subarrays comprises: the control unit is configured to control the reconfigurable network unit to adjust a quantity of antenna subarrays in the horizontal direction comprised in the antenna subarray group connected to the at least one of the K radio frequency channels, wherein beams generated by antenna subarray groups that comprise different quantities of antenna subarrays in the horizontal direction have different widths in the horizontal direction; and the control unit is configured to control the reconfigurable network unit to adjust a quantity of antenna subarrays in the vertical direction comprised in the antenna subarray group connected to the at least one of the K radio frequency channels, wherein beams generated by antenna subarray groups that comprise different quantities of antenna subarrays in the vertical direction have different widths in the vertical direction. the control unit is configured to control the reconfigurable network unit to adjust a quantity of antenna subarrays in the horizontal direction comprised in the antenna subarray group connected to the at least one of the K radio frequency channels, wherein beams generated by antenna subarray groups that comprise different quantities of antenna subarrays in the horizontal direction have different widths in the horizontal direction; and the control unit is configured to control the reconfigurable network unit to adjust a quantity of antenna subarrays in the vertical direction comprised in the antenna subarray group connected to the at least one of the K radio frequency channels, wherein beams generated by antenna subarray groups that comprise different quantities of antenna subarrays in the vertical direction have different widths in the vertical direction.