Heading information is key navigation information for underwater vehicles to perform missions successfully. Conventional underwater heading sensors, such as inertial measurement unit can measure the vehicle’s heading information, but its heading error will be accumulated over time; magnetic compass is susceptible to interference from external magnetic fields, resulting in a lack of effective underwater heading estimation methods. An underwater heading estimation method based on dual-beacon acoustic sensors is proposed in this paper. The dual beacons are deployed on the underwater vehicle with a fixed baseline, and the heading is estimated using the geometric relationship of the dual-beacon design. Considering that many factors may impact heading accuracy in terms of positioning accuracy, depth, and baseline, a multi-dimensional simulation test is designed to quantitatively analyze these effects. The results show that different positioning accuracy, depths, and baselines influence heading accuracy to varying degrees. When the baseline length is 10 m, a change in positioning accuracy from 0.1%D to 2% D leads to nearly a tenfold decrease in heading accuracy.