The present invention discloses an efficient inductor current detection circuit which comprises an inductor current size judgment mechanism circuit, a large inductor current detection circuit and a current mirror circuit which are orderly connected and also comprises a small inductor current detection circuit which is connected to the large inductor current detection circuit in parallel. The inductor current size judgment mechanism circuit is used for judging the relation between the magnitude of the current which flows through an inductor and the magnitude of a preset threshold and outputting a judgment mechanism signal, and thus the large inductor current detection circuit or small inductor current detection circuit is selected to detect the inductor current. The inductor current detection circuit disclosed by the invention is suitable for the inductor current circuit of a BOOST DC- DC converter, the large inductor current can be effectively detected, the effectively low inductor current can be detect, in a large load current condition, the inductor current is scaled down according to a N time proportion, and in a small amplitude current condition, the inductor current is scaled down according to a N/2 time proportion. Thus the accuracy of output end detection is improved well.