A connecting structure for a drill collar of a logging while drilling instrument and drill collar sub male and female joints are provided. The connecting structure for a drill collar of a logging while drilling instrument includes a male connecting joint and a female connecting joint matched with each other. The male connecting joint and the female connecting joint are rotatable relative to each other. Electrical passages are respectively arranged in the male and female connecting joints. One of the male and female connecting joints is provided with a multi-core coaxial electrical male connector connected with the electrical passage, and the other is correspondingly provided with a multi-core coaxial electrical female connector connected with the electrical passage. The male connecting joint is coaxially nested in the female connecting joint. The multi-core coaxial electrical male connector is inserted into and fitted to the multi-core coaxial electrical female connector.