The invention discloses a minimum mean-squared error channel estimate device applied in the wireless sensing net, including a time domain training sequence extraction device, a time domain channel estimate device, a frequency domain channel response conversion device. The invention performs the channel estimation based on the minimum mean-squared error principle through the pilot frequency symbolinserted to the time domain, to obtain the channel time domain response, then obtains the channel response on each sub-carrier to complete the channel estimation through the frequency domain channel response conversion. Due to the linear relationship of the implementation complexity of the minimum mean-squared error channel estimator and the length minimum mean-squared error of the training sequence for estimating, the pilot frequency length inserted in the time domain can be small, thereby effectively reducing the implementation complexity of the channel estimation device, to reduce the implementation complexity by several order of magnitudes compared with the original estimator, applied in the wireless sensing net node.