Coherenee is an important parameter for deseribing the properties of light fields, Understanding theeoherence of light fields is siguificant for optical applications such as interference measurement, holography.and imaging. However, current physical opties experiments rarely involved the control and measurement ofoptieal eoherenee,This paper designs an experimental setup for controlling and measuring the coherenee of lightbeams,using a highly coherent laser as the light souree,A rtating ground glass is used to reduce theeoherence ,and interference is employed to measure the coherenee of the beam.The output laser is expended bya telescope system , which is consisted of two lenses.A rotating ground glass is placed near the foeal point of theexpansion system,By controlling the distanee between the ground glass and the focal point , the coherenee of thebeam can be elfectively controlled. The interferenee experiment measures the contrast of the fringes tocharacterize the coherence prperties of the beam. "This experimental design is simple, easy to adjust , andstraightforward to implement, Through this experiment, a deeper understanding of the deseription andmeasurement of beam coherence is facilitated.