George Bernard Shaw’s representative play Major Barbara is in essence a comedy of political allegory, for it tacitly tackles and answers the question vehemently discussed by a series of men of letters and cultural critics including Matthew Arnold from the 19th century onwards: who shall inherit England? The problem of finding the qualified inheritor for the Undershafts is in actuality that of choosing the best candidates for the future ruling class. As a representative of industrial capitalist class, the powerful Andrew Undershaft achieves overwhelming victories in almost every social aspect, but beyond his (Shaw’s) expectation, the choice of Cusins, a professor of Greek and his future son-in-law, as his successor, is doomed to be a failed decision: unlike the previous generations of the Undershafts, Cusins is not a foundling in any real sense, but a humanist intellectual born into a middle class background, and has never experienced social sufferings, thus lacking the hungry spirit or aggressiveness, which is fundamental to the prosperity of industrial capitalism; in this sense, he is not a qualified successor of Andrew Undershaft and will inevitably fail to carry out the historical mission of English industrial capitalists, just as the historical development of English industrial capitalism from the second half of the 19th century to the present day has already demonstrated. Thus it can be concluded that George Bernard Shaw unconsciously reveals the serious crisis latent in English capitalism of that time: the gradual decline of industrial spirit.