The traditional detection methods based on a single laser displacement sensor are low in efficiency and greatly affected by axial shaking. To address this issue and solve the problems of high-precision and rapid detection of the roundness of the inner cavity section of ultra-long and deep-hole pipelines, this article proposes a point-based detection scheme based on two laser displacement sensors. By formulating mathematical models and numerical simulation, the eccentricity parameters of the rotating shaft of the detection device and the installation deviation parameters of two laser displacement sensors are simulated. The influence of each parameter on the evaluation results of the roundness of the deep hole pipeline is analyzed. On this basis, a mathematical correction model of two laser displacement sensors with installation errors is proposed, and an experimental system for pipeline roundness detection is established to evaluate the effectiveness of the model. Compared with the direct roundness evaluation of the data collected by the two laser displacement sensors, the results show that the roundness evaluation of the corrected data decreases from 0. 30~ 0. 50 mm to 0. 05~ 0. 15 mm, and the measurement time is shortened from 18. 7 s to 9. 8 s.