Abstract: In the temperature control process of a concrete dam, the measured temperature of the thermometers should represent the average temperature of the concrete pouring warehouse so as to monitor the ware house accurately. In this study, the concrete prism model with four kinds of typical water pipe spacings including 1.0 m×1.0 m, 1.5 m×1.5 m, 1.0 m×1.5 m and 2.0 m×1.5 m sections is proposed. First, the temperature field and average temperature process of the concrete prism model with cooling water pipes are obtained by using the finite element method, selecting the typical section of concrete model with the cooling water pipe, and adopting a quadrilateral 12 node isoparametric element to simplify access to any point in the section temperature.Then the geometric position optimization model of the thermometer is established. Finally, an optimization algorithm is used to obtain the optimal geometric position of the thermometer. The analysis results show that the majority of the geometric positions of temperature are close to the average temperature process of the concrete pouring warehouse, the geometry position distribution of the thermometer for 1.0 m×1.5 m section is basically linear, while other sections are of parabolic distribution. If the thermometer is buried in such a geometric position, the measured temperature will be used to represent the average temperature of the warehouse and can be as a reference for temperature monitoring of the concrete dam.