The invention discloses a method for calculating dynamic reserves of a gas field, which comprises the following steps of: a, selecting a standard well, approximately regarding the bottom hole flow pressure of the standard well as block formation pressure, and calculating the bottom hole flow pressure according to a vertical pipe flow model by using wellhead oil pressure; b, establishing a dynamicreserve calculation model by using a pressure drop method under the conditions that the fluid does not generate phase change and the water invasion effect is relatively small under the early formationdevelopment condition; C, according to the dynamic reserve calculation model, calculating dynamic reserves of the block by utilizing data such as gas field cumulative gas production, temperature, single well oil pressure, natural gas high-pressure physical properties and pipe columns; D, verifying a calculation result. Comparing and analyzing dynamic reserve calculation results by utilizing conventional methods such as a yield instability analysis method, a flowing substance balance method, an instability well testing method and the like and a 'standard well'rapid method, and evaluating the applicability of the method. The method can effectively solve the problems that at present, the total gas reservoir shut-in pressure measurement difficulty is high, the formation pressure is difficultto obtain accurately, interference among wells is caused, reserves are eaten separately, and the calculation result is inaccurate.