Hello Mulong ,
it's the standard YOLO output - so confidence, bounding boxes and class. There are two output layers:
Layer name: conv2d_17/BiasAdd/Add, Type: DataType.FP16, Dimensions: [1, 255, 13, 13]
Layer name: conv2d_20/BiasAdd/Add, Type: DataType.FP16, Dimensions: [1, 255, 26, 26]
For decoding, I would look into the official YOLO github repo at examples - how they decode it and display the results.