Robustness of small target detection is a researchable hotspot in infrared surveillance system. The residual phenomenon of background clutter is universal in current local comparison methods. Algorithm of sparse low-rank decomposition restoration cannot be applied to the actual situations due to the long time consumption.This letter proposes a multi-directional cumulative measure(MDCM) to enhance saliency and effectiveness of weak-small target detection. Firstly, multi-directional cumulative mean difference is implemented in central layer and background layer to estimate the background, while the multi-directional cumulative derivative multiplying is calculated in central-active layer to characterize overall target’ heterogeneity, then technology of image fusion is adopted to eliminate interference of false target. Finally, a simple adjudicative technology is employed toward separated target region from complex scenes. Compared to up to date existing approaches,extensive simulational testing on four public datasets prove that proposed approach is capable of separating small targets efficiently from an irregular background in a single-scale window and achieve a comparable or even better accuracy.