A portable toilet odor blocking device includes a container, a foaming liquid, a liquefied gas and a spraying module. The container is formed with an accommodation space. The foaming liquid is accommodated in the accommodation space. The liquefied gas is accommodated in the accommodation space. The spraying module is mounted to the container and configured to use air pressure of the liquefied gas to spray the foaming liquid to a water surface of a toilet, bowl and to selectively spray the foaming liquid to a wall surface of the toilet bowl, such that foam formed by the foaming liquid is configured to completely cover the water surface of the toilet bowl and selectively cover the wall surface of the toilet bowl. Wherein, the foam formed by the foaming liquid is configured to block an odor from excrement above or under the water surface of the toilet bowl.
