The present invention provides a building method and a using method for infant crying implication determining model. The building method is applicable when an infant cries for a specific reason. The building method includes the steps of capturing a plurality of audio characteristics and a plurality of facial image characteristics of the infant, repeating the above step, and using a sorter to respectively integrate the audio characteristics and image characteristics into an audio model and an image model. The audio model and the image model form a determining model. The using method is applicable when an infant is crying, and the using method includes the steps of capturing a plurality of audio characteristics and a plurality of facial image characteristics of the infant, and making a comparison with the audio model and the image model, and if similarities of the audio and the image are respectively higher than a first threshold value and a second threshold value, a reason of the infant crying is determined to be identical to the specific reason when building the determining model.
