Proper arrangement of power distribution network maintenance in countryside by the urgency to reduce times and losses of maintenance outages is concerned by power utilities. A genetic algorithm (GA) for optimum maintenance planning for power distribution networks in countryside is proposed in the paper. The power line sections to be maintained are decoded as that of traveling salesman problems to form chromosomes in order to ensure the genetic operations in the space of feasible solutions, and an improved mutation operator is also presented.A practical example is given and the result shows that the plan obtained by the algorithm cannot only ensure the jobs of maintenance ordered by the urgency but also can reduce times and losses of maintenance outages.