For most of space-frequency joint anti-jamming algorithms, the solution of adaptive steering vector is a high complexity problem. To solve this issue, a space-frequency combined anti-jamming algorithm based on sub-band energy detection (SF-SED) is proposed. At first, the algorithm performs fast Fourier transform (FFT) on the received data of the array antenna and obtains multi-snapshot data of each sub-band through sub-band decomposition. Then, the interference detection statistic and decision threshold are constructed by the energy of the sub-band to judge whether there is an interference in each sub-band. Finally, different methods are used to solve the adaptive weights of the two types of sub-bands according to sub-band classification results. Compared with the related work, the proposed algorithm not only has lower computational complexity, but also has higher output signal-tointerference-and-noise ratio. Theoretical analysis and simulation results demonstrate the anti-jamming performance of the proposed method.