The characteristics of dim point target and background clutter under a complex background are analyzed. A point target detection method based on the omnidirectional multiscale morphology filtering and local characteristic criterion is proposed. The experimental results show that, under the conditions of a complex background and a low signal-to-noise ratio, the detection probability of the proposed method reaches 99.8% with a false alarm probability of 0.1%. The results indicate that, when compared with the methods of Max-median filter, difference of Gaussian scale-space, and Gaussian mixture model, the proposed method possesses a better performance to suppress the complex background, and simultaneously a low complexity and an easy real-time implementation.