The supervision of power is a multifaceted process and behavior, which includes not only the supervision of the executors of public power, but also the supervision of the power of supervision. Both the objective data and the theoretical logic of power supervision show that effective supervision of supervisors is the internal requirement for preventing power corruption and improving the level of corruption governance. Through analyzing the corruption cases of provincial and municipal discipline inspection commission secretaries, it is found that the four basic aspects of supervision corruption are direct intervention in cases, using influence to seek private interests, seeking interests for family members，and improper supervision caused by lack of supervision power. The difficulty in supervising the power of supervision is caused by multiple factors: power has the essential characteristic of expansibility, which makes supervisors have the instinct impulse to avoid supervision; the internal absence of institutional structure makes it difficult for supervision to be effectively implemented; information asymmetry makes external supervision in a powerless state; supervision has hysteresis, which seriously eliminates the exertion of supervision efficiency. It is a complex and systematic project to implement effective supervision on supervision power. At present, it is urgent to seek breakthroughs in the following aspects such as insisting on the synchronous promotion of supervision and restriction, building a scientific and reasonable system of supervision and accountability, and strengthening the quantity supply and quality improvement of the supervision system.