The invention provides a flame detection method based on image target detection, which belongs to the field of image processing, fire detection and video monitoring. The method comprises steps: firstly, a flame detection data set containing flame images and annotation information of each image is built, and the flame detection data set is divided to a training set and a test set; a deep convolution neural network model is built, the training set is used to carry out iterative updating on the model, the test set is used to calculate a loss function for the updated model, and if the loss function for the current model does not drop any more, the model completes training; and a real-time video is photographed, the model which completes training is used to detect each frame of image, if flameexists, the coordinate position of the flame in the image is outputted by the model, and a rectangular frame is used for marking. The phenomenon that features are manually designed for generating a candidate area for suspected flame is not needed, the deep convolution neural network model can be directly used for carrying out flame detection on the whole image, the position information of the flame is obtained, early warning of a fire is thus carried out, and hazards brought by fire can be reduced maximally.