Aiming at the problem that the test results of secondary deformation modulus in some overseas projects are very different because of using codes of different countries, we carry out comparative study of Chinese, German and French codes.We compare the test device, test process, calculation formula and result analysis etc, and analyze the application scope of the three specifications combined with engineering examples.The results show that the codes of China and German are relatively detailed, and test process and result calculation of them are consistent.The French code mainly defines principle, direction, and norms are more general which is not conducive to guide field test.The result of secondary deformation modulus using French code is conservative for sandy soil foundation.It is suggested that when undertaking overseas projects which need to adopt secondary deformation modulus to evaluate treatment effect of sandy soil foundation, Chinese and German codes should be chosen firstly, and it is not recommended to select the French code.