To improve the precision and speed of the system, a new 16-electrode electrical capacitance tomography (ECT) system based on DSP was designed. The measure system adopts 16 electrodes combined and floating capacitance sensor array, and with the phase located loop circuit to eliminate ECT systems additional phase error. The digital signal processor (DSP) is the core of data acquisition system, the computing and control unit includes a DSP (TMS320C5416) and a complex programmable logic device (CPLD). The communication module of the designed system is developed based on HPI parallel transmission technology, which can implement high-speed communication between ECT system and PC. Simulation results show that the sensitivity distribution was more uniform and the reconstructed images for objects were improved obviously by using 16-combined and floating electrodes sensor.