Abstract: NaClO maceration is used to observe the epidermis of plant leaves. Here, we reviewed its use for observing leaf nervation. The Brassica oleracea var. capitata leaf was used as material, and the optimal reaction conditions of NaClO maceration with boiling time, NaOH concentration and treatment time, as well as NaClO concentration and treatment temperature and time were obtained by orthogonal design performed twice. The reaction condition of NaClO maceration for leaf nervation observation was determined. For fresh leaves, the best condition was boiling for 3 min, then 10% NaOH 60°C water bath for 2.5 h, then 3% NaClO 40°C water bath for 2 h.