The invention discloses an automatic perfusion instrument for experimental animal hearts. A semicircular hidden damping groove is formed in the middle position of a semicircular catheter placement chamber. The automatic perfusion instrument is characterized in that after a perfusion catheter is placed in the semicircular hidden damping groove, hidden placement of the perfusion catheter can be realized through the semicircular hidden damping groove and further that the perfusion catheter is not moved in the semicircular hidden damping groove under the effect of damping can be realized. Since a micro-control chip unit and a step driver are arranged in an injection molding shell, and a first perfusion guide pressure roller, a second perfusion guide pressure roller and a third perfusion guide pressure roller are arranged on the inner side of a first power wheel and the outer side of a second power wheel, when a medical solution is perfused into animal bodies, that the dosage and frequency are set according to demands of animals can be realized through the micro-control chip unit, and the step driver further can drive the first perfusion guide pressure roller, the second perfusion guide pressure roller and the third perfusion guide pressure roller to circulate automatically for perfusion.