The invention discloses a precision fixture for improving the balance precision of a wheel, comprising a chuck, a base, a servo motor, a lower pressure plate, a rubber strip, steel balls, an upper pressure plate, a mounting plate, a connecting shaft, a shaft sleeve, a hydraulic cylinder, a bearing end cover, bearings, a guard, an expanding core, expanding flaps, a flange plate, springs, pins, a flange, a connecting shaft and limiting columns. The fixture can meet the requirement for improving the balance precision of a wheel, at the same time, has the characteristics of simple structure, convenient manufacture, stable performance and precision that can meet the machining requirement, and can meet the requirements of automatic production.