As an important equipment in the system of oil drilling rig, the bearing capacity of derrick and base directly affects the safety and benefit of oilfield drilling production. Due to corrosion, wear and load increase in rig derricks and bases due to adverse environmental conditions, it is necessary to link the derricks and bases load capacity with safety assessment techniques to ensure the safety of rig production operations. Therefore, this article focus on the base of the rig derrick and safety assessment of carrying capacity and technological research. Firstly, the finite element simulation is used to find out the maximum stress monitoring position under the lifting condition of the derrick and substructure, and then the fiber Bragg grating monitoring technology is used to monitor the strain of the lifting and lowering of the derrick and substructure, the key structural parts of the drilling rig, and the key stress sections under the working condition, so as to prevent the operation beyond the design capacity and accidents. The test results show that the measured strain values of the derrick and substructure of the drilling rig have a linear relationship with the external force load, and the fitting degrees are 99.48% and 99.85% respectively. The system can monitor the strain of the derrick and substructure, realize the pre-warning and post support of the bearing capacity monitoring of drilling equipment, and more safely ensure the exploration and development of oil and gas resources.