The invention discloses an engine transition connecting plate positioning tool which comprises a rack (1). A base plate (2) is arranged on the rack and is provided with a positioning mechanism (3), aplurality of vertical compression mechanisms (4), a horizontal jacking and butting mechanism (5) and a plurality of bottom face adjusting mechanisms (6); the positioning mechanism (3) comprises a plurality of positioning pins (31) fixedly arranged on the base plate and used for supporting and positioning a product (100); and the multiple vertical compression mechanisms (4) are fixedly arranged onthe base plate (2) in the circumferential direction of the product (100), when the product is placed on the positioning pins (31), the vertical compression mechanisms (4) conduct compression limitation in the vertical direction of the product, the horizontal jacking and butting mechanism (5) conducts compression limitation on the side wall of the product, and the bottom face adjusting mechanisms (6) are used for adjusting the product flatness, and over-positioning is avoided. According to the engine transition connecting plate positioning tool, the product is subject to multi-angle positioninglimitation, and positioning is accurate and stable.