The invention discloses a vertical strain test method considering inherent error. The method takes into full consideration the strain test error caused by deformation of a base support. According to the components of the existing vertical strain sensor, a base support, a transfer rod and an induction rod of appropriate sizes and materials are selected to control the inherent strain test error of the vertical strain sensor, so as to satisfy the accuracy of structure strain test and ensure the reliability of strain test. Meanwhile, the inherent strain test error of the vertical strain sensor is analyzed, a tested strain as close as possible to the actual value is obtained and reflects the actual strain change of the structure, and the precision and refinement of structure strain test are achieved. The method disclosed by the invention can be widely applied to structure test, health monitoring, moving load identification based on dynamic strain, and other technical fields.