The invention provides a high performance mechanical canned motor pump, which comprises a pump body (1), a pump cover (2), an impeller (13), a pump shaft (4), and a bearing box (5), and is characterized in that: a mechanical sealing device (7) is arranged between the front end of the bearing box (5) and an impeller hub or the pump shaft; a mechanical sealing device (8) is arranged between the rearend of the bearing box (5) and the pump shaft (4); a front end plate (50) of the bearing box (5) is provided with a pressure equalizer (20) to make the pressure of an inner cavity (B) of the bearingbox and the inner cavity (A) of the pump cover (2) balanced; and screw pumping rings (3 and 6) and circumfluence holes (53 and 56) are arranged corresponding to the front and back mechanical sealing devices to fully cool and radiate the mechanical sealing devices and a rolling bearing. The high performance mechanical canned motor pump has the advantages of good leakproofness, long service life, safe and reliable use, good functionality and strong adaptive capacity, can be applicable to various working pressures, and fully meets the use requirement on places under working conditions such as high-pressure, toxic, flammable and explosive medium and the like.