The invention firstly aims to provide density measuring equipment, comprising a box body, a plurality of earth pressure cells, a tester and a weighing part, wherein the box body is not provided with an upper cover and is of a cube structure, the plurality of earth pressure cells are arranged at the inner wall of the bottom of the box body, the tester is arranged outside the box body and connected with all the earth pressure cells and is used for reading data from all the earth pressure cells, and the weighing part is arranged separately and is used for weighing. By using the density measuring equipment provided by the invention, the following effects are achieved: a, the whole structure is simplified; b, measurement precision is high; c, the density measuring equipment is suitable for a rockfill material of which the particle size is smaller than 50cm, can meet the real demand and has strong practicality. The invention secondly aims to provide a method for measuring density of rockfill subgrade filler by adopting the density measuring equipment, measurement procedures are simplified, damage on a subgrade does not occur in a measuring process, the accuracy of measurement is high and the practicability is strong.