The daily activity of pigs can be used as an important data base for analyzing and evaluating the health status of pigs. In order to solve the problems of high cost and complexity by using the traditional method of monitoring swinery activity under the farm environment, a monitoring system of swinery activity based on LabVIEW was proposed. By using SRN-2000 passive infrared detector, the information of pig group activities was collected. The circuit, which had high accuracy, multi-channel and real-time operational performance, and took 24 bit ADS1256 chip as its A/D conversion and signal input channel, was designed for a data acquisition system. Based on LabVIEW software platform, real-time acquisition, display and storage of the data were achieved, and a model to monitor daily activity amount was established. Swinery activity amount had been approached by two different activity models: the single sinusoidal model and the double sinusoidal model. A suitable curve was applied and the swinery activity amount was predicted with the improved parameters. The correlation coefficient of single sinusoidal model was lower than the double sinusoidal model so that the later one was adopted. Test results for pigs which just entered the circle showed that the correlation coefficient of the daily activity amount model was 0.83. Through calibrating by using the data of the experimental station and the validation in the real farm, it was proved that the swinery activity amount could be fairly explained by the model.