Abstract: In the first half of the 19th century, under the influence of Ireland's internal economic depression and the growth of British demand for labor, Irish labors moved to Britain on a large scale. Participating actively in the production activities of emerging industries, agriculture and urban service industries, they became a force that should not be ignored in the process of British industrialization. Irish labors promoted capital accumulation and the development of industrial economy by replenishing high quality labors, improving the labor structure and lowering labor price. However, they also had a certain negative impact on social security and public health in Britain. The fact that Irish labors participated in and promoted the British industrialization shows that the industrialization of Britain is the result of joint efforts of four major ethnic groups in United Kingdom.