Radio frequency (RF) coils are an important component of magnetic resonance imaging (MRI) equipment. However, the field of ultrahigh-field RF coil research is fraught with technical challenges which limit the development of magnetic resonance technology. Thus, the research on the performance of ultrahigh magnetic field RF coils is a primary focus on the study of the ultrahigh-field MRI system. The development of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> H/ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sup> P dual-nuclear RF coils based on the ultrahigh-field MRI system is greatly significant for the research on the diagnosis and metabolism changes of many disease conditions such as tumors. In this paper, a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> H/ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sup> P dual-nuclear multi-channel RF coil for the ultrahigh magnetic field 7 T MRI was proposed. The performance of the proposed coil was evaluated by using a numerical co-simulation approach, and phantom studies were conducted on the Siemens 7 T MRI system. The results demonstrate the feasibility of the proposed double-nuclear RF coil in the application of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> H/ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sup> P ultrahigh magnetic field MRI.