Magnetic resonance imaging (MRI) is a noninvasive medical imaging technology with a high spatial resolution. We aim to design a single-channel radiofrequency receive coil with an optimized signal-to-noise ratio (SNR) for various field intensities in MRI. We propose a method that maximizes the SNR through surface current optimization using the target field method. The proposed method can design a dedicated coil shape by solving an objective function with terms related to the signal, coil resistance noise and sample resistance noise. We found coil shapes for a rat kidney model in the case of static magnetic field intensity |𝑩 0 | = 7 T, 0.3 T and 6.5 mT as an example. Our method will enable the design of single channel receive coil for preclinical applications of small animals.