Abstract: As a kind of special networked control systems,internet of things control system is the extension and expansion of Networked Control Systems．Based on the analysis of system structure,the impact of sampling period on network load and control performance,the simulation research about delay of Internet of things control system was carried out．For there kinds of typical cases of zero delay,fixed time delay and variable delay,the impact on system performance was quantitatively analyzed．According to the delay distribution under different load conditions,the related simulations were finished．Simulation conclusions are as follows:reducing forward channel delay can improve system performance,random delay on Internet of things control system impact more seriously than the fixed delay.

Key words: Internet of things control system (IOT CS),Delay,Network load,System performance