The physical basis is examined concerning the correlation between total radi-ation and net surface radiation by virtue of the equation of surface radiation balance,demonstrating the rationality of R=bQ-a. Based on the bulk of measurements,studiesare made of the correlation between their instantaneous values and their daily andmonthly totals. Results show that the correlation between their instantaneous values isthe highest, that between their daily totals may decrease owing to the daily changes insurface albedo and cloudiness,and that between their monthly totals is high, which generally has somethimg to do with some kind of mutual compensation of the annual cyclesof surface albedo and effective radiation.