The invention discloses a productivity evaluation method based on combined constraint of a well bottom dynamic curve and a wellhead inflow dynamic curve. A novel wellhead binomial productivity equation is deduced based on a deep analysis of the well bottom binomial productivity equation theory, and gas well productivity is calculated directly based on the wellhead pressure. For the same gas well, the open flow capacity under any conditions is uniquely determined, therefore, the open flow capacity calculated through the well bottom binomial productivity equation and the open flow capacity calculated through the wellhead binomial productivity equation are at the same value theoretically. Based on the theory, productivity evaluation based on combined constraint of the well bottom dynamic curve and the wellhead inflow dynamic curve is realized by writing a program, to a certain extent, the problem that a result of the open flow capacity determined only through the well bottom binomial productivity equation is inaccurate is solved, and thus reasonable production allocation of the gas well on the mine field is better guaranteed.