The effects of line-tying on resistive tearing instability in slab geometry is studied within the framework of reduced magnetohydrodynamics (RMHD).citep{KadomtsevP1974,Strauss1976} It is found that line-tying has a stabilizing effect. The tearing mod
e is stabilized when the system length $L$ is shorter than a critical length $L_{c}$, which is independent of the resistivity $eta$. When $L$ is not too much longer than $L_{c}$, the growthrate $gamma$ is proportional to $eta$ . When $L$ is sufficiently long, the tearing mode scaling $gammasimeta^{3/5}$ is recovered. The transition from $gammasimeta$ to $gammasimeta^{3/5}$ occurs at a transition length $L_{t}simeta^{-2/5}$.
