Concentration is an important physical quantity to describe the properties of a solution. It changes with the change of temperature. Based on the method of ultrasonic grating measurement of sound velocity in transparent liquid, taking transparent sodium chloride solution as an example, the relationship among sound velocity, concentration and temperature is studied through the control variable method. Finally, the equations of these three parameters is obtained quantitatively, and the concentration is measured at different temperatures. The results show that the method has high confidence and small relative error, and is widely applicable to the measurement of transparent liquid concentration. It has the advantages of high timeliness, short response time and high precision.