The timely and high-quality completion of PTT (power transmission and transformation, PTT) project construction has a decisive impact on the power supply quality and efficiency of the power system. So in the construction of PTT projects, we must do a good job in the management and control of construction efficiency and construction progress. The traditional mode of construction progress monitoring of PTT projects is mainly adopts the manual monitoring mode, which is time-consuming and labor-intensive. In order to realize the intelligent monitoring of construction progress of PTT projects, this study proposes an intelligent monitoring method of construction progress of PTT projects based on Mask-RCNN. This method first uses the marker recognition model based on Mask-RCNN to recognize the markers of key nodes in PTT projects, and then judges the construction progress according to the calculation rules for construction progress of PTT projects. We selected 21 kinds of PTT project markers to carry out experiments, and the results showed that the average accuracy of the marker recognition model based on Mask-RCNN can reach 92.16%, which effectively proved the effectiveness of the model. In addition, this article used the proposed method to analyze the construction progress of the Shiyan Hanshui 500kV PTT project, and the results showed that our method could effectively monitor the construction progress of the PTT project. It proved that our method had great application market and potential.