Objective To evaluate the safety of magnesium borate ore powder (MBOP) as a molluscicide, especially for the arsenic content in the soil samples from the fields used MBOP over more than one year. Method The arsenic in the soil samples was assayed by using the AgDDTC method recommended by the government. Result In all of the soil samples, the arsenic contents did not exceed the national health criterion. However, the arsenic in the MBOP treated soil samples was higher than that in the control one′s. Conclusion The application of MBOP as a molluscicide in the fields does cause some side effects on the environment.