The goal of this thesis is to automatically mark the ultrasound images of the pericardial effusion. Use U-Net architecture and change encoder part to other pre-trained models. This thesis fills up the image black border to make the side length a multiple of 32, let dataset can use on our model, use IOU and Dice of correct rate calculation methods to verify the most suitable model. The average mIOU of the final validation set of this thesis reached 70%, which is nearly 10% higher than the IOU of all parts of the U-Net. Using the generated heart area trend can assist doctor more information.