With the development of solar radio spectrometer, it is difficult to process a large number of observed data quickly by manual detection method. Yunnan astronomical observatories (YNAO) have two solar radio spectrometers with high time and frequency resolution. An automatic detection method of solar radio burst for decimetric and metric data of YNAO is proposed in this paper. The duration of solar radio burst was counted and analyzed. Channel normalization was used to denoise the original solar radio image. Through experimental comparison, Otsu method was selected as a binary method of solar radio spectrum, and open and close operations were used to smooth the binary image. Experiments show that the proposed method for automatic detection of solar radio bursts is effective.