To solve the problem of laser spot center detection problem in fire extinguishing training system,a simple and practical detection algorithm is presented based on the analysis of tradition detection methods. Firstly,the captured image is filtered by Gaussian filter to remove noise. Secondly,white and red color component are retrieved in HSV color space. Thirdly,a cross window around candidate point is constructed to identify spot according to the size of laser spot. Finally,laser spot center is calculated based on the rectangle which is surround spot. The method is simple,does not need background prediction,and can be applied to multiple backgrounds or complex illumination environment. The experimental results show that the algorithm is effective.