Speech recognition is a hot topic in the field of artificial intelligence. Generally, speech recognition models can only run on large servers or dedicated chips. This paper presents a keyword speech recognition system based on a neural network and a conventional STM32 chip. To address the limited Flash and ROM resources on the STM32 MCU chip, the deployment of the speech recognition model is optimized to meet the requirements of keyword recognition. Firstly, the audio information obtained through sensors is subjected to MFCC (Mel Frequency Cepstral Coefficient) feature extraction, and the extracted MFCC features are input into a CNN (Convolutional Neural Network) for deep feature extraction. Then, the features are input into a fully connected layer, and finally, the speech keyword is classified and predicted. Deploying the model to the STM32F429, the prediction model achieves an accuracy of 90.58%, a decrease of less than 1% compared to the accuracy of 91.49% running on a computer, with good performance.