Abstract: To provide a basis for the application of nano magnesium hydroxide in the remediation of Cd pollution in soil and the safe production of vegetables, a field experiment was carried to study the effect of different levels (0, 2.25, 4.50, 6.75 kg/hm2) of common magnesium hydroxide and nano magnesium hydroxide on yield, content and Cd forms in Brassica peckinensis, and the pH value and the content of Cd chemical forms in soil. The results showed that the yield of B. peckinensis increased by 4.1%-22.3%. After the application of magnesium hydroxide, Cd contents in leaves, petioles and roots of B. peckinensis decreased by 5.3%-19.2%, 9.0%-28.1% and 3.5%-19.3%, respectively, and the Cd content in soil decreased by 8.2%-41.5%. The Cd content in leaves, petioles and roots of B. peckinensis treated with nano magnesium hydroxide was obviously lower than that with common magnesium hydroxide at the same application rate. After the application of magnesium hydroxide, the content of protein bound Cd (NaCl-F) in shoot of B. peckinensis decreased, while the content of residual Cd (R-F) in shoot increased, and the soil pH value, the content of FeMn-Cd, OM-Cd and RES-Cd in soil decreased. In general, the highest yield and the lowest leaf Cd content of Chinese cabbage was found in low-level nano-magnesium hydroxide 2.25 kg/hm2 (NMg1) treatment, which had the best effect of remediation of soil Cd pollution in our study.