According to the principle of the parametric array, the difference frequency sound of the parametric array loudspeaker has high directivity. This high directivity can make the difference frequency sound only emit to the target area, without polluting the sound environment outside the target area. Currently, there are two projection modes for using parametric array loudspeakers, namely ① directional mode and ② reflection mode. In addition to directly focusing on the audience (directional mode), the parametric array loudspeaker can also project the sound beam to the surface, thereby forming a virtual loudspeaker at the reflection point (reflection mode). In these two modes, if the direction of the sound beam produced by the parametric array loudspeaker can be further adjusted mechanically or electronically, it will be easier to apply to applications with tracking functions. Currently, in the design of parametric array loudspeakers, there are mainly two types of directivity control methods: mechanical methods and signal processing methods. The mechanical method is built with an electric rotating table and reflective objects, while the signal processing method is implemented with analog circuits or digital processors. The biggest disadvantage of the mechanical method is that its overall size is too large, and the extra reflection caused by the mobile rotating table and reflective objects is too large. There are three main types of directivity models: product model, improved product model, and convolution model. The work on beam width control of parametric array loudspeakers is relatively less. This chapter firstly concludes with a brief review of directional control methods, directional models, and directional design, followed by a focus on the implementation of difference frequency sound beam steering in parametric array loudspeaker using fractional delay filters. Based on the pump wave product model of the directivity of the difference frequency sound, a simulation study was conducted on the beam steering of the secondary sound field of the parametric array loudspeaker, and then the delay of the phased parametric array loudspeaker at different steering angles was obtained. By comparing the total passband error and the instantaneous maximum error, the parameters most suitable for the performance and cost of the Farrow structure small filter were determined. The selected parameters were compared with the Lagrange interpolation algorithm, and the results demonstrated a good level of agreement within the specified bandwidth. The Farrow fractional delay filter was built using the DSP Builder tool, and the phased parametric array loudspeaker system was implemented on the FPGA platform, and the beam steering was experimentally verified in the anechoic chamber.