The invention discloses a relay protection data synchronization method for an active power distribution network. The method comprises the following steps: respectively extracting fault time accordingto fault features at two sides of a protected circuit, and then acquiring the current zero-crossing point time before the fault time, taking the zero-crossing point time as the standard, and taking the data at one side as the reference, and synchronously correcting the data at the other side by utilizing an interpolation method, thereby aligning the data at two sides. For guaranteeing the reliability of the fault detection, the fault occurrence can be regarded when continuous three sampling points are in mutation. The method disclosed by the invention is independent of the external clock, an operation of adding the additional equipment is unnecessary, so that the method cannot be influenced by the element that the fault detection delay, the sampling delay and the channel delay are inconsistent.