A beamforming method, comprising: Calculating an uplink channel frequency response; calculating a model parameter in a channel frequency response mathematical model based on the uplink channel frequency response and each uplink subcarrier frequency, wherein the model parameter has reciprocity on uplink and downlink subcarrier frequencies; constructing a downlink channel frequency response based on the model parameter, the channel frequency response mathematical model, and each downlink subcarrier frequency; calculating a beamforming weight of each downlink subcarrier frequency based on the downlink channel frequency response; and performing downlink beamforming on an antenna array based on the weight, wherein the antenna array is a dual-polarized antenna array or a single-polarized antenna array; wherein the model parameter comprises a distance of each path, an angle of arrival of each path, an amplitude of each path, and an initial phase of each path; and wherein the channel frequency response mathematical model is based on an antenna array which comprises an array having a uniform array element spacing; and wherein the channel frequency response mathematical model is expressed as follows: F k i = ∑ n = 1 N a n e jφ n e − j 2 π λ i d n e − j 2 π λ i k l cos θ n, wherein F ( k, i) represents the channel frequency response mathematical model, n = 1, 2,..., N represents a number of a path, N represents a quantity of paths, d n represents a distance of an n th path, θ n represents an angle of arrival of the n th path, a n represents an amplitude of the n th path, Φ n represents an initial phase of the n th path, λ i represents a wavelength corresponding to an i th subcarrier frequency, i = 1,2,..., I represents a number of a subcarrier frequency, I represents a quantity of subcarrier frequencies, k = 1, 2,...,K represents a number of an array element, K represents a quantity of array elements, and l represents an array element spacing. Calculating an uplink channel frequency response; calculating a model parameter in a channel frequency response mathematical model based on the uplink channel frequency response and each uplink subcarrier frequency, wherein the model parameter has reciprocity on uplink and downlink subcarrier frequencies; constructing a downlink channel frequency response based on the model parameter, the channel frequency response mathematical model, and each downlink subcarrier frequency; calculating a beamforming weight of each downlink subcarrier frequency based on the downlink channel frequency response; and performing downlink beamforming on an antenna array based on the weight, wherein the antenna array is a dual-polarized antenna array or a single-polarized antenna array; wherein the model parameter comprises a distance of each path, an angle of arrival of each path, an amplitude of each path, and an initial phase of each path; and wherein the channel frequency response mathematical model is based on an antenna array which comprises an array having a uniform array element spacing; and wherein the channel frequency response mathematical model is expressed as follows: F k i = ∑ n = 1 N a n e jφ n e − j 2 π λ i d n e − j 2 π λ i k l cos θ n, wherein F ( k, i) represents the channel frequency response mathematical model, n = 1, 2,..., N represents a number of a path, N represents a quantity of paths, d n represents a distance of an n th path, θ n represents an angle of arrival of the n th path, a n represents an amplitude of the n th path, Φ n represents an initial phase of the n th path, λ i represents a wavelength corresponding to an i th subcarrier frequency, i = 1,2,..., I represents a number of a subcarrier frequency, I represents a quantity of subcarrier frequencies, k = 1, 2,...,K represents a number of an array element, K represents a quantity of array elements, and l represents an array element spacing.