This paper points out the limitation of Beck formula and gives a revised formula owing to the water content and ²²² Rn escape in soil for calculating γ radiation dose rate through the experimental fitting from 576 sets of measured values in Zhejiang Province. When the revised formula is applied to Beijing Municipality, where there is a great difference in the meteorology and soil conditions, the calculated average in general is only 3.5% different from that measured; those of every position deviate only 2.1% averagely; and their dispersion is in the experimental errors. Therefore, the revised formula possesses a high reliability and a broad suitability, and is an effective method to estimate the γ radiation dose rate on the land.