The continuous spectra of the substars with surrounding protoplanetary disks were calculated .
The results reveal that protoplanetary disc average temperature decreases to 3 K during the period of 5 Myr for substars with masses 0.01 M _ { { } _ { \bigodot } } and during the period of 160 Myr for substars with masses 0.08 M _ { { } _ { \bigodot } } .
Estimations of protoplanetary discs flux maximum depending on the substar mass at the age of 1 Myr are : 4.6 kJy ( for 0.01 M _ { { } _ { \bigodot } } ) and 3.4 MJy ( for 0.08 M _ { { } _ { \bigodot } } ) .
Maximum of protoplanetary disc radiation before it reaches the temperature of the cosmic microwave background changes within the ranges : from 0.07 mm to 0.58 mm ( for substar mass 0.01 M _ { { } _ { \bigodot } } ) and from 0.02 mm to 0.29 mm ( for substar mass 0.08 M _ { { } _ { \bigodot } } ) .