An online weighing method for poultry was proposed to meet the demand for online weight grading and weighting of poultry which were carried out on a suspension transportation device. The mechanical model of drawing tension was developed by a force analysis to suspension chain conveyors which was used for butchering the poultry. The method of different weighing heights was proposed to estimate the draw tension of chain and the weight of objects was calculated according to the estimated drawing tension. A weighting test device for the poultry weighting was established. At first, a simulation experiment was carried out and the Matlab and SimMechanics were used to simulate the procedure of online weighting. The results showed that correlation coefficient was 0.99914 between Dvalue and drawing tension, and the object weight deviation from simulating estimation to drawing tension was within 15.7g. Then the experiments were conducted on the same test device and the results showed that correlation coefficient was 0.76 and the correlativity between Dvalue and drawing tension was significant at a significant level of 0.10. The maximum error was 125.03g when the object weight was calculated according to Dvalue. The study suggested that it was realistic to get the object weight on the basis of drawing tension, and the online weighing for poultry carcass could be realized through further improving the measurement accuracy.