Nucleic acid aptamers are a kind of one-dimensional biological nanomaterials and have found many applications. This paper designed and implemented a polymerase chain reaction (PCR) amplification device with a reaction volume of 500 μL, which can be used for the amplification of nucleic acid aptamers of tumor cells in the aptamer selection. This device mainly includes a control module, a temperature measuring module, a PCR amplification tube, a metal tank module, a liquid crystal display (LCD) and operation module and a cooling module. The new PCR amplification chamber is matched with the designed metal tank to ensure the temperature uniformity of the PCR amplification solution. The control module based on the STM32F103RCT6 manages the workflow of the entire device. The PCR amplification chamber and PT100 sensors on the metal tank formed a closed-loop feedback system, and the incremental proportional-integral-derivative (PID) algorithm was used to achieve the precise temperature control. In addition, we introduced the Smith predictive compensation algorithm to solve the temperature hysteresis problem of the PCR amplification chamber. The experimental results showed that the PCR device can meet the requirements for the nucleic acid aptamer selection of tumor cells. The device can also be used in other experiments with large-volume PCR amplification.