The advantages and disadvantages of the technology of harmonic detection was put forward after the harmonic detection technology based on a linear neural network, the network structure of harmonic detection, and introduces the principle of harmonic detection. Focus on the application of LMS algorithm to adjust the network weights analysis. Finally constructs containing the odd harmonics of the load current, linear neural networks method using Hanning window using the MATLAB software of FFT algorithm and the simulation experiment is carried out, in the noise free and noisy environment. The experimental results show that the detection accuracy, harmonic detection method of linear neural network has better based on.