The invention discloses a point cloud amount square algorithm based on an irregular object. The method specifically comprises the following steps that after data is obtained through preliminary scanning, preprocessing is carried out through a data preprocessing unit, a picture is analyzed according to a cargo detection picture to generate point cloud data, missing data is filtered and compensatedin a space segmentation mode, and data transformation is carried out. The method relates to the technical field of cargo volume calculation. According to the point cloud amount square algorithm basedon the irregular object, on the basis of 3D point cloud data, an irregular object volume calculation model is established; a maximum value (max) and a minimum value (min) are found out for the Z_labeldata according to the projection area; equal-interval data segmentation is carried out according to the data length (max-min), the area of a segmentation plane is calculated according to the size ofa projection area in a projection plane, an infinitesimal thought is proposed according to the data characteristics of 3D point cloud to segment an irregular object, an approximately regular object issegmented, then volume calculation is carried out, and the obtained calculation effect is more accurate.