The invention relates to a device for measuring the uniformity of the fluorescent powder on the inner wall of an energy saving lamp tube, which is characterized by comprising a computer, a multifunctional data card, a preamplifier, a measuring light detector, a reference light detector, a rotating turntable, a turntable driver, a laser light source, a semi-transparent and semi-reflecting mirror and a lamp tube to be measured, wherein the lamp tube to be measured is clamped on the turntable which can be rotated in the range 360 DEG C; the turntable is controlled by the computer; and a part of laser which is emitted by the laser light source is emitted from the inner side of the lamp tube through a fluorescent powder coating after being reflected by the semi-transparent and semi-reflecting mirror and received by the measuring light detector, and the other part of laser is irradiated to the reference light detector through the semi-transparent and semi-reflecting mirror. The device provided by the invention has the advantages of simple structure and high automation degree and can accurately and comprehensively measure the thickness and uniformity of the fluorescent powder coatings ofvarious energy saving lamp tubes with different shapes.