By means of data simulation, the laser ranging data, attitude data and location data of portable coal inventory instruments under ideal conditions are simulated. According to the actual situation, each error parameter is determined and brought into the simulation data. By comparing the theoretical volume with the simulation volume after errors introduced, the influence laws of all kinds of error factors on volume are obtained. The producing mechanism for each error is analyzed and the influence degree of each error factor on volume is compared. The above research results provide a theoretical basis for the suppression or compensation of main error factors in the portable coal inventory instruments.