The invention discloses a method for improving the PTP time synchronization precision of an intelligent substation. The method comprises the following steps: configuring exchangers to a P2P mode of IEEE1588 protocol; selecting a network partitioning point; modifying the attribute of exchangers on two sides of the partitioning point; and respectively connecting the partitioned networks into a clock source. According to the 1588 partitioning method, a series of exchangers are partitioned into a plurality of sections, the attributes of uplink ports of exchangers at the partitions are modified, forwarding of clock message can be limited, and the clock source is added into the network of each partitioned section, so that the number of cascade exchangers of each network can be reduced, time link time delay and jitter can be greatly reduced, and the reliability and accuracy of network time synchronization can be greatly improved.