The invention provides a simplified cylinder-shaped pipeline fatigue strain monitoring method. Three strain sensors are evenly distributed along the periphery of the outer wall of a cylinder-shaped pipeline at a monitoring position in parallel. The maximum strain of the pipeline and the included angle between the maximum bending strain and a first sensor are computed, and the maximum bending strain force and the strain direction of the cylinder-shaped pipeline are obtained. Compared with the existing monitoring method, a sensor is removed, a computing method is simplified, detecting equipment power loss is lowered, reliability is improved, and directions of loads such as ocean current do not need to be considered.