The invention discloses a radar radiation source recognition method based on a deep learning strategy and a multitask learning strategy and mainly aims to solve the problem that recognition accuracy is low in the prior art. The method comprises the implementation steps that 1, an original radar radiation source signal is subjected to data preprocessing; 2, envelope features, fuzzy function features, slice features, cyclic spectrum features and frequency spectrum features of the preprocessed radar radiation source signal are extracted, and values of the features are linearly transformed into [0,255] and saved as an image set; 3, a convolutional neural network (CNN) is designed, and the multitask learning strategy and a random inactivation strategy are introduced into the CNN; and 4, four feature training sets are used to train the CNN, then four trained CNN models are utilized to classify four feature test sets, and a radar radiation source recognition result is output. The method is high in recognition accuracy and can be applied to electronic intelligence reconnaissance, electronic support reconnaissance and radar threat warning systems.