Abstract: Cone penetration detection has the advantages of in-situ, continuity, high efficiency and resolution. The use of marine cone penetration detection results to estimate the bearing capacity of offshore platform pile foundation has a great application potential. This paper takes the pile foundation of a platform in the Chengdao sea area of Shengli Oilfield as an example. The ROSON100 marine cone penetration device was used to conduct in-situ detection around the platform's legs. Simultaneous drilling sampling and indoor geotechnical parameters testing were implemented. The results of cone penetration detection and geotechnical tests were used to estimate the bearing capacity of platform pile foundation, respectively. The similarities and differences between three different calculation methods of bearing capacity of pile foundation were discussed. The results show that the overall trend of the pile side friction resistance obtained by these three methods is basically the same with the buried depth. Based on certain regional engineering experience, the pile tip resistance and single pile ultimate bearing capacity obtained by the drilling specification method and the CPT indirect method are basically consistent. The pile tip resistance and the ultimate bearing capacity of single pile obtained by the CPT direct method are obviously larger than the former two. The ultimate bearing capacity of pile foundation shows good compatibility for these three calculation methods under the premise of considering silty sand as the bearing layer. The findings can provide a new reference for the calculation of the bearing capacity of offshore engineering pile foundation.