The present disclosure provides an adapter and an LED lamp using the adapter, the adapter including a first body with an upper portion and a lower portion, a first electrical connection member electrically connected with the LED lamp and including at least one conductive post, a second electrical connection member with an end electrically connecting with the first electrical connection member, the other end thereof connected with an external electronic control member, and including a first protrusion with a plurality of installing holes fixing with a plurality of conductive splints therein, the external electronic control member including a third electrical connection member with a plurality of terminals therein, the lower portion including a first wall with a first recess for inserting the first protrusion therein, the plurality of terminals rotated to insert into the plurality of conductive splints for electrically connect the adapter with the external electronic control member.