Infrared small target detection is extremely important in military guidance,early warning and border spy UAV detection in military field. However,due to the lack of texture information,high background clutter,dim and fuzzy and low contrast of infrared small targets,there is still space for progress. In this paper,a small infrared target detection scheme based on bio inspired model (PLMC) is proposed. Firstly,the target is enhanced and background clutter is suppressed based on the bio inspired model. Then use improved threshold to filter false targets and extract real targets. The results of experiments on multiple complex scene datasets show that the scheme proposed in this paper has better detection performance and robustness compared with other relatively new small target detection methods.