1. A dynamic delay curve generation method for an ultrasonic imaging system that includes a transducer array having a plurality of transducer elements with each transducer element corresponding to a position x. The angle between a line joining a beam reflection point to the center of the transducer array and the vertical centerline of the transducer array is defined as &thgr;, the sampling cycle is defined as T R, the fine resolution cycle is defined as &Dgr;t 0, and beam speed is defined as V, and that the ultrasonic imaging system also includes a parameter decoder, comprising the steps of: obtaining three initial values of K 0, N 0 and &phgr; 1 from the parameter decoder, where K 0 is the initial delay weighted parameter, N 0 is the initial delay cycle number and 8 φ 1 = 1 - x 2 &it; cos 2 &it; θ N 0 &it; V 2 &it; T R &it; Δ &it; &it; t 0 defining A&equals;N 0 &plus;&phgr; 1, B&equals;1&plus;N 0, C&equals;&phgr; 1, D&equals;0, E&equals;0, K&equals;K 0 ; executing B&equals;B&plus;1, D&equals;B&plus;E, E&equals;C&plus;2; determining if A&lE;0, and if A&lE;0 is false, executing step (5), on the contrary, if A&lE;0 is true, executing step (6); executing A&equals;A&plus;C and then executing step (3) again; and executing A&equals;A&plus;D, C&equals;C&plus;1 and at the same time executing K&equals;K&plus;1, where the delay weighted parameter K is used for controlling the delay of response signal received by each transducer element, finally executing step (3) again.