[Objectives] Aiming at the current situation that traditional lightning rod evaluation methods are difficult to efficiently evaluate its protection probability, an efficient numerical evaluation algorithm for lightning rod protection probability is developed based on the electrical geometric model and attractive volume to realize the efficient calculation of lightning protection probability at any point in space. [Methods] This method first determines the attractive volume boundary of the lightning rod and the protective object according to the interception process of the upward leader and downward leader. Then calculates the lightning surface and exposure arc from the lightning strike distance, the attractive risk and interception effect of the lightning rod can be quantified evaluated. Finally, the two characteristics of lightning rod on attraction and interception are integrated to establish a numerical evaluation model of protection probability. [Results] To verify the accuracy of the method, the general rule of lightning rod probabilities of protection are analyzed, and the results are compared with the existing analysis method. It shows that the evaluation results of this method accord with the actual law. [Conclusions] This method has a high degree of quantification. It can realize efficient calculation of lightning protection probability for any point in space, which is helpful for lightning protection design work.