The possibility of the detection of circumstellar clouds around hot stars have been shown based on the analysis of observed equivalent widths of resonance line 2852 Mg i of interstellar origin. An attempt has been made to combine two methods, earlier suggested — ‘Method of Doublet 2800 Mg ii’ and ‘Method of Depression’ — for the determination of the parameters of circumstellar clouds. The sequence of the determination of these parameters is illustrated on the application of this combined method for circumstellar clouds around five hot stars. The value of the mean absorption coefficientk 0 for the system of resonance lines in the region of depression ∼2400 Å, is obtained. An application of the conception of spectral classification of circumstellar clouds has been realized.