Current distribution line protection in smart grid can’t be solved well in low sensitivity and unsatisfied rapidity by protection principle nowadays. The wavelet analysis has a strong feature-extracting function, which can extract the fault signatures of the fault phase. In this paper, the EMTP is used to make simulations and wavelet transformations of power line-end short-circuit failure, fault-phase supply voltage crossing zero, single-phase grounding fault of transmission line through high impedance, transitional fault, etc., showing the parameter selection of wavelet transformation used in optimization design of phase selection component for line protection.