The invention relates to a handcart type switch cabinet of a transformer substation and specifically relates to a method and a tool for detecting insertion depth of a handcart type switch cabinet. The method includes the following steps of disconnecting and grounding a power source of the handcart type switch cabinet; measuring depth B of the end of a fixed contact (1) and the outer edge of a fixed contact seat (3); measuring depth R of a chamfer contact point on a moving contact (4) of the handcart type switch cabinet and the end of the moving contact (4); measuring depth A of the position of a pushed positioning plate (2) and the end of the fixed contact (1); calculating depth L of insertion of the contact point of the moving contact (4) into the fixed contact (1), that is, the depth L=the depth A-the depth B-the depth R. The method and the tool have the advantages of being low in cost, convenient to use, simple in manufacture and structure, reliable in judgment, rapid in operation, measurable and capable of being inserted, saving work time, improving work efficiency and avoiding potential safety hazards.