This paper investigates thermodynamic and economic performances of a small-scaled (1-2 MW) industrial park trigeneration system in China through dynamic simulation (using TRNSYS software). The trigeneration system is composed of internal combustion engine, absorption chiller, heat exchangers and electric chiller. Electric demand management method is applied to configure the system. In Mode 1, electricity produced by internal combustion engine is only supplied to customers. Power consumed by electric chiller is purchased from power grid. In Mode 2, all the electricity consumed in the system is produced by internal combustion engine. The monthly power, cooling and hot water loads of the system are calculated. Results show that Mode 2 has better thermodynamic performance. Primary energy ratio can be as high as 123%, and exergy efficiency is 51%. Energy saving rate is 17.53% and it can reduce 699.05 t of CO2 annually compared to separate production system. In addition, a natural gas-driven system has lower life cycle costs than a diesel-driven system. The additional investment of the former system can be paid back in 1 year. Both initial investment and annual payments of Mode 2 are higher than those of Mode 1 when they use the same fuel.