Happiness is the fundamental pursuit of people, labor is human nature activities, and labor is the basic human right. People realize human nature through labor, and the deep pleasure experience is labor happiness. Labor justice is not a labor right but a moral basis for the realization of labor happiness. The justice of the labor subject is the essence of labor happiness. The essence of the justice of the labor subject is that the usefulness of labor to the social subject exceeds the harmfulness. The justice of the means of production is the object justice of the labor happiness. The people are the co-owners of natural resources such as the land, and the means of production produced by labor should belong to the producers. Labor motive justice is the deep motive of labor happiness. The realization of labor happiness should become the fundamental motivation for people to work. Labor process justice is the key link to labor happiness, and the fundamental requirement to ensure labor process justice is to fully protect labor rights.