Nowadays, more and more parents are paying increasing attention to the penile length of their children. At present, the methods of measuring penile length mainly include manual measurement and ultrasonography. The former can be used to measure the flaccid, stretched and erected penile lengths, and its use for measuring the stretched penile length has been internationally accepted for its precise definition, unified description, and high repeatability. The latter, as a new method, is being gradually accepted for its imaging visualization and measurement accuracy. This article reviews different measurements of penile length in the mainstream literature of recent years, with an analysis of their advantages and disadvantages.