Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) technologies were used to determine the contents of trace elements in Isatidis Radix and Isatidis Folium at different growth times. Among them, the contents of trace elements including Cr, Co, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Li, Be, V, Ga, U, Nb, Zr, Bi, Th, Er, Yb, Y, and Sc were measured by ICP-MS, while the elements Fe and Al were measured by ICP-OES. According to the test results, the trend of the contents of 24 trace elements in Isatidis Radix and Isatidis Folium at different growth times indicated certain similarity. The contents of 24 trace elements in Isatidis Radix reached the lowest value between July and September, then gradually increased and reached the highest value in November. The contents of those elements in Isatidis Folium all reached the highest point in August and November. Based on the results of trace element content changes, the preliminary inference was made that the optimal harvest time for Isatidis Folium is August and November, and the optimal harvest time for Isatidis Radix is November, which means that Isatidis Folium and Isatidis Radix can be plucked at the same time. The method is easy and fast, has good precision and accuracy which to some extent lays a foundation for the study of nutrient transport patterns of Isatidis Radix and Isatidis Folium.