The invention relates to a lossless uniform updating method for power software definition network flow tables. The method includes the steps that when forwarding and exchanging equipment is idle, system time is applied for to an integrated controller according to set frequency; the integrated controller sends the system time to the forwarding and exchanging equipment, and the forwarding and exchanging equipment updates the system time; the forwarding and exchanging equipment is inquired about the updating time of the flow tables; the forwarding and exchanging equipment reports the updating time of the flow tables to the integrated controller; the integrated controller sends a network overall flow table updating threshold value; the forwarding and exchanging equipment updates the flow tables, and new flow tables are started within set threshold value time of the integrated controller. Information interaction between the integrated controller and the forwarding and exchanging equipment is achieved through the method, flow table updating threshold values of all the forwarding and exchanging equipment are unified, the updating uniformity of all the forwarding and exchanging equipment flow tables is guaranteed, and the network packet loss probability of a power software definition network is substantially decreased when the flow tables are updated.