Nineteenth-century English society faced the problem of poverty and employment. Many reforms and social investigations made by governments or non-governmental organizations thus followed in this era. These social investigations made two major contributions: First is to reflect real social condition and to promote the efficiency of reform. Second is to let people realize the living condition of the working class. This article will examine the life and works of Henry Mayhew (1812-1887). Different from most social investigations of his time, Mayhew used on-the-spot investigation to point out the reason why the working class was poor in the nineteenth-century England.