Through appearance, it can distinguish the automobile bulb, the welding spot is smooth and firm, the lamp head is bright and free of scratches; the bubble shell has good transparency and no obvious gas lines and bubbles; the assembly of the visual filament, lamp head and bubble shell should be correct and symmetrical; the wick is neat and skew no more than 5 degrees; the bonding agent connecting the bubble shell and the lamp head is not exposed and evenly bonded; the steel seal of the lamp head is clearly typed, with brand and specification, and some products And the batch number of the certification number. According to the photoelectric parameters, we can distinguish the automobile bulb. If possible, we can use instruments to check whether the current, luminous flux and service life of the bulb meet the parameters specified in the relevant standards and judge whether it is qualified or not. Through the mechanical strength, we can distinguish the automobile bulb, take the lamp cap and the bubble shell and screw it to know whether the lamp cap and the bubble shell are firmly bonded; lightly touch the bubble shell on the wooden table and gradually exert force to judge the thickness and strength of the bubble shell; press the lamp cap skin and the foot with the fingernail to see whether they are deformed and judge the strength. When buying a car bulb, find out the purpose of the bulb, and determine whether it is a car bulb and which part of the car is used. Not easy to buy, such as "vacuum tungsten halogen bulb", pure fake.