The invention discloses a prefabricated type cable trench, comprising a main trench frame body and light trench sections, wherein the end surface of the main trench frame body is U-shaped; the end face of each light trench section is in the shape of an inverted trapezoid with an upper opening; inserting grooves corresponding to the light trench sections in shape are symmetrically prefabricated inthe two ends of the main trench frame body; the main trench frame body serves as a main force bearing piece, the wall thickness of the main trench frame body is larger than that of the light trench sections, and the length of the main trench frame body is smaller than that of the light trench sections; the light trench sections serve as cable trench length splicing bodies; the ends of the light trench sections are inserted into the inserting grooves in the end face of the main trench frame body; and the light trench sections and the main trench frame body are sequentially connected to form theprefabricated cable trench. The self-weight of the main trench frame body and the light trench sections is obviously reduced, and joint filling treatment can be omitted due to the inserting connection mode between the main trench frame body and the light trench sections. During field installation, the main trench frame body and the light trench sections are more convenient to construct and operate, the installation efficiency is improved, and the construction process is simplified. The light trench sections can be sleeved and stacked up and down during transportation, so that the occupied space is saved, the transportation cost is reduced and the transportation efficiency is improved.