In order to simulating the formation of coronal surges, the characteristics ofmagnetic reconnection caused by the resistive tearing instability in bipole-monopolemagnetic field are studied numerically by using a two-dimensional, time-dependent,compressible magnetohydrodynamic simulation. The results show that the magneticlines of the bipole and monopole fields will reconnect directly and the evolution ofmagnetic field leads to a whip configuration under a magnetostatic basic state whichincludes three regions ── a bipole, a current sheet and a monopole. The upwardplasmoid supported by bended magnetic field diffuses and falls back to solar surfaceafter reaching its maximum height. The upward velocity of plasmoid reaches 0.10vA
is Alfven velocity in bipole magnetic field). The simulated result confirms thatthe formation of coronal surges may be related closely to magnetic reconnection inbipole-monopole magnetic field.