The invention discloses a robot weak light environment grabbing detection method based on a multi-task sharing network, and belongs to the technical field of computer vision and intelligent robots. According to the method, strict matching of shot images in a weak light environment and a normal light environment is ensured through image acquisition, a corresponding data set d is constructed, then Darknet-53 is adopted as a backbone network to construct a weak light environment capture detection model, multi-scale features with strong feature expression ability are extracted, and, through a parallel cascade capture detection module and an image enhancement module, capturing detection and weak light image enhancement tasks are realized respectively; training samples are randomly selected from the data set d, a weak light environment capture detection model is used for prediction, and when the change of a loss value within the iteration number iter is smaller than a threshold value t, the capture detection model G is converged, that is, training of the model G is completed; and an image Ilow shot in the weak light environment is input into the trained model G to obtain a predicted capture frame parameter and an enhanced image, and a capture detection task in the weak light environment is completed.