In this paper we suggest a method of estimating the electron-energy spectral index (6) from the microwave radiation power spectral index (a). We have also given a tesult of the correlation statistics between the radio radiation power spectral index and the proton-energy spectral index, of which correlation coefficient is 0.70. The results of calculating 6 for the burst of August 7,1972 show that electron-energy spectrum can be approximately represented by a power-law distribution at the rise time before the peak, but deviated from the power-law distribution after the peak. The range of the values of 6 is about 0.4-3.6 at the impulsive phase of the bursts. The results of the computation also show that there is no second accelaration step presented for the white light flare of August 7, 1972. This conclusion is supported by the result of the correlation statistics, and it is also consistant with the SMM observations during the 21th cycle SMY.