An apparatus and method for detecting the volume of a liquid drop, and a method for adjusting the volume of a liquid drop are disclosed, so as to improve the convenience in making adjustment and measurement, and to alleviate a measure error. The detecting apparatus includes at least one measuring unit, where each of the at least one measuring unit includes: a first measurement groove, at least one second measurement groove, and a third measurement groove arranged adjacent to the second measurement groove, where the capacity of the first measurement groove is more than the total capacity of the second measurement grooves, the height of a sidewall of the first measurement groove shared by the second measurement groove arranged adjacent thereto is less than the height of a sidewall of the first measurement groove not shared by the second measurement groove.