The invention provides a calculation method of the sound field of a circular arc-shaped linear ultrasonic phased array, comprising a beam control focusing algorithm, a sound field calculation method and the influence of structural parameters on sound field characteristics. The calculation method uses an angle method to show the position information of an energy converter array element so as to deduct the beam control focusing algorithm of a circular arc shape linear phased array energy converter; a circular array element is similar to a rectangular array element and is combined with coordinate conversion to calculate the sound field of the circular arc-shaped linear phased array; the method is performed with simulation verification respectively by Reily integration and non-paraxial approximation multi-Gaussian models, and the obtained result is very identical. In addition, the calculation method analyzes the influence of structural parameters on sound field characteristics and provides theoretical basis for designing and optimizing the energy converter.