This paper develops a new separated mini-environment to provide a constant temperature chamber for the placement of Micro/Nano-metrology instrument. In this paper, the rule of temperature change with time under natural convection and coercive convection is presented. The measurement and control system is composed of TEC, programmable power source and precise temperature measurement system. The mathematic model of the constant temperature chamber is identified making use of system identification theory and system identification toolkit of MATLAB. The temperature stability is improved by applying auto-adaptive PID method. Experiments show that the temperature fluctuation of a single-point is less than 0.02°C and the whole field is within 0.05°C. The goal of high-precision temperature control is achieved.