Image Quality of Magnetic Resonance Imaging (MRI) has several factors including SNR dan CNR. Influence Factors of SNR depends on the coil used. MRI shoulder joints in several hospitals can be done with different RF Coil, there are M coil flex and shoulder coil. Are there differences in image quality with MRI shoulder joints between the two coils. This study was conducted to determine differentiation SNR and CNR between them in the coronal proton density sequence of MR shoulder joint. This research was quantitative research with an experimental approach. Scanning was done by using Flex M Coil and shoulder coil with 10 samples. The quality image evaluated of SNR and CNR, data were analyzed using paired t-test with α = 5%. The results of the research showed significant differentiation of image quality between using Flex M Coil and shoulder coil in coronal proton density-weighted of MRI Shoulder Joint with p-value SNR < 0,001 and CNR = 0,002. The average of SNR and CNR using shoulder coil is higher than using flex M coil, so the shoulder coil has the better image quality of coronal proton density-weighted MRI shoulder joint.