The invention, which belongs to the reactive power optimization field, especially relates to a flexible target reactive power optimization model with a voltage infeasible node and a solving algorithm thereof. The model comprises two collaborative optimization sub models: a voltage control model at a weak region and a reactive power optimization model at a non-weak region. And the model is solved by using a parallel collaborative evolution algorithm including a population successive updating strategy. According to the model provided by the invention, weak region identification can be realized automatically; the model has an integrated calculation characteristic of weak region identification and model solving; a reactive power optimization infeasible problem can be solved; and the active network losses as well as the lower limiting exceeding degree of the node voltage at the weak region can be reduced.