The invention relates to a method for testing double string suspension mode of 500 kV common type composite insulators, which has technical characteristics that: arranging 500 kV common type compositeinsulators in an artificial iced test climate chamber to construct a test system for double string suspension mode of 500 kV common type composite insulators; by adjusting a high voltage spacing anda low voltage spacing, achieving various test arrangements of the double II type spacing, an inverted V-shaped spacing and angles to meet test conditions; and carrying out snow slush covered flashovervoltage testing under the arrangement of 500 kV common type composite insulators in a double string parallel connection with different center spacing, inverted V-shaped string type and different center angle arrangement. According to the method for testing double string suspension mode of 500 kV common type composite insulators, based on the change of double II type spacing, an inverted V-shapedspacing and angles on the 500 kV common type composite insulators, double string suspension mode of 500 kV common type composite insulators are tested; it is taken as a complete test method with system integrity, test for double string suspension mode of 500 kV common type composite insulators in different regions and levers can be guided, and the method has the characteristics of comprehensive accuracy, easiness in implementation and the like.