In serious geological disasters, long-distance buried oil and gas pipelines usually suffers large deformation. If the deformed pipe has a defect, it will easily lead to pipeline body failure, and finally serious environmental pollution and economic loss. Accurately obtaining the deformation of pipelines and conducting safety assessment can play an important role in ensuring the safe and stable operation of pipelines. Based on the inertial measurement unit (IMU) data, the strain analysis algorithm adopted wavelet transform to reduce noise and design codes to recognize feature, which could effectively identify hot bends, cold bends, pipe laying with elastic bending, and key attention sections on pipelines. In order to conduct strain-based safety assessment of the girth weld, the calculated bending tensile strain value of the pipe section was combined with the tensile strain capacity prediction model proposed by ExxonMobil. In the background of high-grade oil and gas pipeline based on strain design had been widely used in domestic oil and gas transportation industry, pipeline safety assessment of girth weld in high-grade steel pipelines can be carried out by adopting the method of this paper.