Several nuclear charge radii had been calculated based on the law of A1/3 and isospin dependence Z1/3 formula which had been used to describe the charge radii data. It is achieved that the isospin dependence Z1/3 formula is superior to the generally accepted A1/3 law through mean root square deviation analysis, that is, the Z1/3 formula is more effective to describe the charge radii data. Several nuclear charge radii had been calculated based on the law of A1 / 3 and isospin dependence Z1 / 3 formula which had been used to describe the charge radii data. It is achieved that the isospin dependence Z1 / 3 formula is superior to the generally accepted A1 / 3 law through mean root square deviation analysis, that is, the Z1 / 3 formula is more effective to describe the charge radii data.