During the factory acceptance test of cracking gas compressor for a 1,200 kt/a ethylene plant, the radial bearing pad temperatures of low-pressure and medium-pressure cylinders exceeded the performance assessment indicators. This could be caused by the abnormal friction between the bearing pads and the shaft or by insufficient supply of lubricating oils which leads to poor heat dissipation. Excessively high bearing pad temperatures can cause thermal degradation of lubricating oils, leading to the formation of soft contaminants that deposit on the surfaces of bearing pads and shaft, and resulting in carbonization, sludge or even varnish. This reduces the lubricating and cooling effects of lubricating oils, accelerates the wear of bearing pads, and severely affects the long-term operation of cracking gas compressor. Since cracking gas compressor is one of the key core equipment in ethylene plant, its stable operation time directly determines whether the ethylene plant can achieve a safe, stable, long-term, full-load and optimum operation. Therefore, a comprehensive and scientific analysis shall be made for the causes of high bearing pad temperature, and a treatment plan shall be developed to solve this problem, so as to meet the mechanical trial run acceptance standards for compressors.