An adaptor is for electrically connecting with pins of an electrical connector. The adaptor includes an insulating housing, a pair of crimping connectors, and two connecting members. The insulating housing includes two holes. The crimping connectors are accommodated respectively in the holes. Each crimping connector includes a first crimping portion for electrically connecting to one of the pins and a second crimping portion together formed with the first crimping portion. The connecting members are electrically connected with the crimping connectors respectively. Each connecting member includes a first end, a cable, and a second end. The first end is electrically connected with the second crimping portion. The cable is electrically connected with the first end. The second end is electrically connected with the cable, wherein the second end has a through hole. A testing device for testing the electrical connector is also disclosed.