Abstract: The concept of justice refers to the distribution of economic resources that reflects a certain degree of “equality of outcome”. Discussions of the Poor Laws in the 19th century are one of the main manifestations of the concept of Justice in Classical Economics. Adam Smith was the first to change the perception of the poor, asserting that those in poverty inherently have the right to receive certain material resources. Malthus sharply criticized the Poor Law based on his population theory, arguing that it would create a continuous supply of the poor, ultimately dragging society into widespread poverty. Ricardo supported Malthus's views, using his wage theory along with Malthus's population theory to advocate for the repeal of the Poor Law. Senior played an important role in the reform of the Poor Law and was a key proponent of the New Poor Law enacted in 1834. The discussion of Poor Laws was the first “equity versus efficiency” debate in the history of economics. Issues of group equity and intergenerational equity can also be traced back to the debates on Poor Laws in classical economics.